EPSRC Projects in Microwave, Millimetre-Wave and THz Research · M1. Demonstration of devices with switching time < 10 ns M2. Demonstration of a high-speed buck converter MMIC –

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EPSRC Projects in Microwave, Millimetre-Wave and THz Research

WF12

Professor Peter Gardner

The University of Birmingham

[email protected]

Slide 2 of 108

Workshop Programme

WF12 EPSRC Projects in Microwave, mm-wave and THz Research

14:20 – 14:25 Welcome and Introductions 14:25 – 15:00 EPSRC RF and Microwave project portfolio and future strategic directions and ambitions. Matthew Scott, EPSRC 15:00 – 15:30 Ultimate Electromagnetics and Novel Materials: QUEST, SYMETA and Graphene, Prof. Yang Hao, Queen Mary University of London 15:30 – 16:00 Integration of RF Circuits with High Speed GaN Switching on Silicon Substrates Dr K. Elgaid, Glasgow; Prof. P. Houston, Sheffield; Prof. P. Tasker, Cardiff 16:40 – 17:10 Informed RF for 5G and Beyond Dr Pei Xiao, Surrey 17:10 – 17:40 FARAD: Frequency Agile Radio. Prof. Tim O’Farrell, Sheffield; Prof. Mark Beach, Bristol 17:40 – 18:10 Low THz Technology and Applications: TRAVEL, Micromachined Circuits for THz Comms, and PATHCAD. Prof. M.J. Lancaster; Dr M. Gashinova; Prof. P. Gardner. Birmingham. 18:10 – 18:20 Open Discussion and Concluding Remarks

Slide 3 of 108

EPSRC RF and Microwave project portfolio and future strategic

directions and ambitions.

Matthew Scott

EPSRC

[email protected]


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Ultimate Electromagnetics and Novel Materials: QUEST, SYMETA and

Graphene

Prof. Yang Hao

Queen Mary University of London

[email protected]


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Integration of RF Circuits with High Speed GaN Switching on Silicon Substrates

Paul J Tasker, Johannes Benedikt & Jonathan Lees (Cardiff University), Peter Houston & Kean Boon Lee (Sheffield University), Khaled Elgaid &

Iain Thayne (Glasgow University), Colin Humphries & David Wallis (Cambridge University), Andrew Forsyth (Manchester University)

[email protected]


Slide 6 of 108

Project


GaN on Si Technology Platform o GaN HFETs is a technology of choice for Power Electronics

• High Efficiency Switching Amplifiers

o GaN HFETs is a technology of choice for RF/Millimeter Wave Electronics • High Efficiency Carrier Amplifiers

o Advantageous to have a common platform • On Silicon for manufacturability and integration

o Building on Established Expertise • GaN on Si Power Electronics (PowerGaN)

• Millimeter Wave Integrated Circuits

Integration of RF Circuits with High Speed GaN Switching on Silicon Substrates - £2.56M Project Running from July 2016 to June 2019

Slide 7 of 108

Motivation (1)


Output Power

Gain

Efficiency

Linear Non-Linear

Maximum

Required

Power

capability

from the

amplifier

The amplifier

operates

most of the time

in the average

power region

Peak

Power

8dB

Average

Power

Probability Density

Distribution Function (PDF)

Crest Factor Reduction

Clipping!

Peak to Average Power Ratio PAPR

Power Amplifier Efficiency Challenge - problem with non-constant envelope modulation

Slide 8 of 108

Motivation (2)


Linear Non-Linear

Peak

Power

8dB

Average

Power Issues

• Bandwidth of input signal is significantly increased x5

• PAPR of input signal is increased (Crest Factor Reduction)

• Requires high speed DAC and ADC

• Requires complex digital computation and so consumes Power

! "#!! "#$

ADVANCES IN PREDISTORTION

TECHNIQUE

DPD system components:

1. Engine to synthesize the predistorted output

2. Coefficient identification and updating algorithm

3. Transmitter observation receiver to monitor linearity

Digital predistortion block diagram 18

Source: Boumaiza

WAMICON 2015 Plenary Talk

Feedback

Transmit

Digital Pre-distortion (DPD) - allows for operation in the non-linear region

Slide 9 of 108

Amplifier Concepts


PA1 Digital

Baseband

+

Signal

Division

+

Up

Conversion PA2

S

Concepts

• Chireix Amplifier (Constant Envelope Operation - LINC)

• Doherty Amplifier (Modify RF Output Load))

• Envelope Tracking (Modify Drain Bias)

Input

Digital

Information

Output

Modulated RF

Carrier

Advanced Amplifier System Concepts for high PAPR Signals - Accommodate/modify the Efficiency/Power Characteristic (and Linearity?)

Baseband

Frequencies - Switching Amplifier

Carrier Frequencies - RF Amplifier

Slide 10 of 108

Materials and Devices

Peter Houston (Sheffield University)

[email protected]


Slide 11 of 108


Requirements for Envelope Modulators

The Envelope Modulation will be formed by the driver, the Half Bridge and the output filter

Full integration from gate driver to RFPA required

Gate driver has to be integrated with power switches

HFET switches will need to operate at the limit of their frequency and efficiency

Digital/RF interface critical

Envelope signal

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Device Challenges

Project milestones M1. Demonstration of devices with switching time < 10 ns M2. Demonstration of a high-speed buck converter MMIC – target bandwidth 200 MHz (requires switching time < 1 ns), current handling up to 3 A and voltage 50 V (already demonstrated in PowerGaN) M3. Incorporation of a 600 mA gate driver circuit (need to keep simple) integrated with M2 above M4. Design and realisation of RF PA module MMIC suitable for 5 GHz M5. Demonstration of integration of envelope modulator and RFPA

GaN Cap AlGaN Barrier

GaN Channel GaN Buffer and AlGaN Transition

Silicon Substrate

Drain

SiNx Passivation

Gate Dielectric Source

Gate

2DEG

Source Field Plate • Depletion mode devices can be

used (easier than enhancement mode devices)

• Basic device technologies already developed

• Need to push switching speed to the limit and fully integrate to avoid parasitics

Slide 13 of 108

Integration of GaN Power and RF Devices


• A key challenge for the integration of GaN Power and RF devices is the development of a common epitaxy platform

• GaN power devices • Conducting substrate preferred to allow grounding of the back plane of

the device • GaN RF devices

• Insulating substrate preferred to prevent coupling of RF signal to free carriers

• Also need to consider • RF Loss due to coupling of passive circuit elements with free carriers in

substrate • Response time of traps in the GaN buffer which control effects such as

leakage, “current collapse”, “punch-through” and “kink”

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Comparison of Substrates for GaN RF Devices


Substrate Substrate

Cost

£/cm2

Thermal

conductivity

W/cmK

Lattice

mismatch to

GaN

Thermal

expansion

mismatch to

GaN

Residual

strain at RT

SiC 10 4.2 Compressive

(3.5%)

Tensile

(-29%)

Close to zero

Sapphire 1 0.23 Compressive

(16%)

Compressive

(34%)

Compressive

Si 0.1 1.5 Tensile

(-17%)

Tensile

(-54%)

Tensile

• SiC has best materials performance, • Low mismatch, high conductivity, Insulating • but cost is high

• Si has many challenges, but • cost is low • large wafer sizes (150mm and 200mm) allow low cost processing in Si foundry • Is the preferred substrate for GaN Power devices

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Materials Challenges to be Address in Project

DCIV

0

100

200

300

400

500

600

700

800

900

1000

0 5 10 15 20 25

Drain Voltage (V)

Dra

in C

urr

ent (m

A/m

m)

f0510 4x75_0d

Substrates

Buffer layers

Barrier layers

Channel

Scaling of barrier layer - Optimised ns

- Optimised gate control

Group III diffusion in to Si substrate. - Control of substrate conductivity

Optimum buffer thickness -Reduced coupling to substrate - Stand off voltage

Buffer layer doping. - Fe vs Carbon - Kink in IV characteristics - Current Collapse - Control of Punch Through

Control of surface states

Kink

AlGaN vs AlInN - Optimised ns

- Reliability

Channel thickness

Double Heterostructures?

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Wafer ID Anneal

time/temp

(secs/oC)

Rsheet

(ohms/sq)

Comment

substrate-1 - 183000 As received

substrate-2 - 340000 As received

1900 900/1175 1326 Clean reactor

1925 1500/1225 7118 Coated

reactor

• Average Rsheet = 1326 ohms/sq

• Minimum Rsheet = 503 ohms/sq

Resistivity Map of Wafer 1900

• GaN RF devices are often produced on high resistivity Si (upto 10k ohm.cm)

• However, after GaN Growth Si resistivity can be significantly reduced due to

• Thermal cycling

• Group III atom diffusion

• Note significant non-uniformity of substrate resistivity

• Thermal generation of carriers can also affect substrate resistivity

• Typical device junction temp >150oC

Effect of GaN Growth on Hi-Res Si Substrates

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GaN High Electron Mobility Switching Transistor (HEMT)

D

G G

S

8mm 0 2 4 6 8 10 12 14 16 18 20

0

100

200

300

400

500

600

700

800

900

1000

1100

I DS(m

A/m

m)

VGS

(V)

VGS

= -11 to +2 V

VGS

= 1V

Ron

= 4.22 mohm

D-MODE HEMT

DC characteristics

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Switching Characteristics

Current switching times ~100 ns but significant room for improvement!

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Devices and Circuits

Khaled Elgaid (Glasgow University)

[email protected]


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Outline


o Why RF/Switching GaN on LR Si MMIC?

o RF GaN on LR Si Devices/MMIC Technology Challenges

o GaN on LR Si HFETs Initial Results

o MMIC on LR Si Interconnect/Passives Initial Results

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Why RF/Switching GaN on LR Si MMIC?


• RF Market (2014) $1.98 Billion

• Base Station dominates

• GaN forecast for 2020 ~ 50% of base station

• Market expected to grow

Ref: CSI 2016 (ABI Research 2015 & SEDI)

Competition

• LDMOS

• BipolarSi

• GaAs

• SiC

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RF GaN on LR Si MMIC, Technology Challenges


Substrate

Transmission Media

RF Losses

Thermal conductivity

W/cmK

SiC Low RF loss

< 1.5 dB/mm

@ 60GHz

4.2

Sapphire Low RF Loss

< 1.5 dB/mm

@ 60GHz

0.23

Si Very High RF Loss

> 20dB/mm

1.5

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Transistor technology Insulating Buffer Thickness < Source/Drain gap

Highest reported fT/fmax GaN on low resistivity silicon transistors

Combined with passives, can leverage potential of GaN and economy of scale of Si

6” MOCVD epi from Cambridge

σ< 40Ω.cm

RF GaN on LR Si HFETs,

Initial Results

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GaN on LR Si MMIC Interconnect, Decoupling Techniques


Low loss transmission line technology on LR Si

Performance meets loss specification of < 1.5 dB/mm @ 67 GHz

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a) shunt b) series

MIM capacitors Fabricated using BCB - MS on LR Si

Measured and Modelled of Shunt and Series Capacitors Show good agreement

SEM Image shunt

Equivalent Circuit Model

series

GaN on LR Si MMIC Passive Devices, Decoupling Techniques

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Electromagnetic Simulation

Substrate is not shielded

Substrate is shielded

Plot of gain and radiation efficiency for both single and elevated stack antenna

Measured and Simulated reflection coefficient of stacked rectangular patch

antenna

GaN on LR Si MMIC Passive Devices, Decoupling Techniques

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Summary


• Common Technology Platform based on GaN on Si for both Power and RF

Electronics o Collaborative Team (Cambridge, Cardiff, Glasgow, Manchester & Sheffield

Universities) • Materials, Devices & Circuits (Both Power and RF Electronics)

o Building on Established Expertise

• Envelop Tracking Power Amplifier o Provides a very challenging “Proof of Concept”

• High Bandwidth and Efficiency Requirements

• Both baseband and RF

• Strong Industrial/Agency collaboration o Selex, MACOM, Thomson, DMD, New Edge, Plessey, NXP, IQE, KNT, Oxford

Instruments, Rohde & Schwarz, DSTL, ESA

Integration of RF Circuits with High Speed GaN Switching on Silicon Substrates - £2.56M Project Running from July 2016 to June 2019

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EPSRC Projects: Informed RF for 5G and Beyond

Dr Pei Xiao

University of Surrey

[email protected]


Slide 29 of 108

• 5G requirements

• Vision and Approach

• Project Outline, Scope & Milestone

• Objectives

• Expected Impacts

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5G Performance Requirements

Low Latency

Ultra Fast Data Transmission

High Energy Efficiency

Uniform User Experience

Massive Connectivity

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5G usage scenarios

• Enhanced Mobile Broadband (e.g. for smart phones)

• Massive Machine Type Communications (e.g. for massive sensor nodes)

• Ultra-reliable and low latency communications (e.g. for connected cars, remote e-health)

Massive Machine Type Communications

Ultra-reliable and Low Latency Communications

3D video, UHD screens

Smart City

Industry automation

Gigabytes in a second

Mission critical application,

e.g. e-health

Self Driving Car

Augmented reality

Smart Home/Building

Work and play in the cloud

Voice

Future IMT

Augmented reality

Industry automation

Mission critical application e.g. eHealth

Self-driving car

Enhanced Mobile Broadband

Gigabytes in a second 3D video, UHD screens

Work and play in the cloud

Smart Home/Building

Voice

Smart city

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Capacity Crunch Problem

• Channel capacity is the tightest upper bound on the rate of information that can be

reliably transmitted over a communications channel, it is determined by bandwidth W

and signal-to-noise ratio SNR.

• Capacity/Spectrum crunch problem: we need to find solutions to address the radio

spectrum scarcity problem – limited available bandwidth W.

Slide 33 of 108

Current RF and DSP Design

Antenna and RF

Design

DSP Design

• Previous work has been focused either on the radio frequency (RF) or digital

signal processing (DSP) aspect without major regard to the other.

o In the former case, the conventional RF design fails to exploit the full

potential that a co-designed system has to offer.

o In the latter case, DSP algorithms are devised under the orthogonality

assumption without considering the impairments caused by limitations and

imperfect nature of the physical hardware, antenna, radio propagation and

RF/microwave front-end electronics.

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Vision

• Spectrum crunch problem can be largely mitigated by leveraging

the degrees of freedom (DoF) inherent in the wireless systems

which have not been fully exploited in the current systems.

• The disjoint RF and DSP design cannot fully exploit the DoFs.

• RF impairments, nonlinearities, interference can, in certain

circumstances, contain useful information, thus provide additional

DoFs that can be advantageously utilised.

• Maximum spectral efficiency is achievable only through the joint

RF-DSP design that permits access to those DoFs.

Slide 35 of 108

Joint DSP-RF Approach

• We propose RF-DSP co-design to

o Fully utilize the DoFs in conventional areas like space, time and

frequency;

o Explore new dimensions of DoFs in other domains, such as

antenna DoF in polarisation and beam-space, and additional DoF

in interference, nonlinearities, RF impairments.

o Maximize the spectral efficiency of the existing available spectrum;

o Fully utilize the new mm-wave spectrum.

Slide 36 of 108

Polarisation Modulation

• The polarisation of a radio

wave can also be utilised to

carry information bearing

signals

• The distinction between the

polarisation status of radio

waves can be made by the

rotation direction of an

elliptically (or circularly)

polarised electric field.

• Modulation order can be

increased by using elliptical

polarisation.

• Channel effect can be

compensated by DSP design

Slide 37 of 108

Beam-Space MIMO

• Independent data-

streams are mapped

onto an orthogonal set

of beam patterns in the

antenna far-field

• Single-RF chain (low

complexity, low power

consumption)

• Compact antenna

dimension

Slide 38 of 108

Beam-Space MIMO

• Electronically steerable parasitic

array radiators (ESPARs)

• Fourier Rotman Lens (FRLs)

Scalable solution for mmWave

communications

Parallel beam processing

low latency

Slide 39 of 108

• Increased directivity of transmission by beamforming techniques can

dramatically

Reduce interference

Save signal power

Increase coverage and capacity

• Beamforming techniques are important for 5G small cells and mm-

wave.

Beamforming

Slide 40 of 108

RF vs Digital Beamforming

• RF beamforming can achieve diversity gain, extend the transmission range, has lower complexity, power consumption and cost. However it cannot support multi-streaming, and suffers high loss at phase shifters.

• Digital beamforming can support multi-streaming, but incurs higher complexity, power consumption and cost.

Slide 41 of 108

Joint RF and Digital Beamforming

• Hybrid beamforming demonstrates a performance comparable to all-digital arrays, but at significantly lower cost and power consumption.

• We investigate massive MIMO solutions using large ESPAR and FRL arrays by means of hybrid RF and digital beamforming.

Slide 42 of 108

Master Diagram of the Project

Slide 43 of 108

Work Plan and Deliverables

Work Plan

Year 1 Year 2 Year 3

WP Name of the WP/Milestones Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

WP1 Nonlinearity Assessment & Utilisation in Dirty RF Surrey

1.1 Behavioural modelling/assessment of nonlinearity components

1.2 Utilisation of I/Q imbalanced signals & nonlinear distortions

1.3 Utilisation of nonlinear distortions in multicarrier systems

1.4 Utilisation/mitigation of RF impairments in PM systems

1.5 Utilisation/mitigation of RF impairments in BS-MIMO systems

WP2 Polarisation Modulation/multiplexing Surrey

2.1 Non-coherent polarisation modulation antenna and DSP

2.2 Reconfigurable EPM antenna and DSP for 5G small cell

2.3 Combined polarisation and conventional modulation

WP3 Beamspace MIMO under Hardware Constraints QUB

3.1 Optimal BS-MIMO model with hybrid BF architecture

3.2 BS-MIMO assessment/correction under hardware constraints

3.3 Design and fabrication of hybrid FRL & ESPAR beamformers

3.4 Implementation of large-scale FRL & ESPAR architectures

WP4 Proof-of-Concept QUB/Surrey

4.1 Implementation of BS-MIMO transceiver for 5G radio access

4.2 Undertake empirical evaluation for the developed schemes

Deliverables:

WP1 M6: Modelling of nonlinearities; M18: RF impairments/nonlinearity utilisation algorithms for I/Q imbalanced systems and multicarrier

systems; M24: DSP algorithms for PM systems; M26: DSP algorithms for BS-MIMO systems.

WP2 M6: Non-coherent PM antenna and DSP design; M12: EPM antenna and DSP design; M21: Combined PM and conventional modulation

design.

WP3 M6: Hybrid BF architecture design; M12: Joint RF-DSP design for BS-MIMO; M18: Design and fabrication of hybrid BF; M24:

Implementation of large-scale FRL-ESPAR architectures.

WP4 M33: Prototype for BS-MIMO transceiver; M36: Final system evaluation.

Slide 44 of 108

Project Status

• Work allocations: UoS (WP1, WP2, WP4)

QUB (WP3, WP4)

• Starting date: June 1, 2016;

Ending date: May 31, 2019

• Industrial partners:

Slide 45 of 108

Objectives

• Provide solutions to meet 5G requirements

Ultra-fast data transmission

Low latency

High energy efficiency

Massive connectivity

• Contribute to three major 5G usage scenarios

Enhanced broadband experience

Massive MTC

Reliable and low-latency communications

Slide 46 of 108

Expected Impacts

• Brings together different disciplines (DSP, RF & Microwave

Communications, RF & Microwave Devices) to yield

disruptive technologies for future wireless networks.

• Provides solutions to tackle the spectrum crunch problem.

Slide 47 of 108

Thank you

Frequency Agile Radio

FARAD

Timothy O’Farrell1, Mark Beach2

1Department of

Electronic & Electrical

Engineering

University of Sheffield

2Electrical and

Electronic Engineering

Dept

University of Bristol

EMC, August 2016

Outline

Vision and Research Streams

Workpackage Flow

Workpackage Activities

The Research Team

Industrial Partners

FARAD© Universities of Sheffield and Bristol 201649


Aim and Challenge

Aim This project aims to address the expected capacity crunch by

focusing on the RF bottleneck in 5G, beyond 5G and legacy

wireless networks through researching and developing miniature,

integrated, reconfigurable and tuneable, multiband radios to

enable ‘spectrum agile’ radio access and concurrent multiband

operation.

ChallengeThe realisation of a software radio (SR) system based on a single

chain radio architecture, providing concurrent multiband/

multimode transmission capabilities over 0.4 – 6 GHz spectrum.

Vision

Separable,

Tunable,

Multiband,

Integrated

Radio

Transceivers

to support

Multimode

and carrier

aggregation

From

450 MHz to

6 GHz

Re

qu

ire

me

nts

As

su

mp

tio

ns

Ev

alu

ati

on

Fra

me

wo

rk

Ha

rdw

are

in t

he

Lo

op

Te

st

Be

d

Antennas/ Filters

PA/ Linearization

LNA/ Cancellation

ADC/ PAPR


Work-Package Flow


53

WP1: Antenna Sub-system

Objectives: This research will focus on tuneable antennas to achieve frequency selectivity

and concurrent multiband operation within the frequency range from 690 MHz

to 6 GHz.

Project Progress: Accomplished tasks

1. Dual-band tuneable antenna for test-bed covering frequency range from

560MHz to 1.1 GHz [1].

2. Triple bands tuneable antenna covering frequency range from 600MHz to 3

GHz.


Dual-band Antenna

54

WP1: Antenna Sub-system

Project Progress: Current tasks

Rebuild the triple bands tuneable

antenna with low loss substrate

materials and DTCs to improve the

antenna radiation performance.

Project Progress: Future tasks

1. Characterize the DTCs based on

triple bands tuneable antenna.

2. Increase the antenna tuning range to

cover up to 6 GHz.

3. Investigate fixed multi-band antenna

with tuneable filters.


Tuning

higher band

Tuning

Lower band

WP2: Frequency Agile Transmitter

ObjectiveDesign of power amplifiers for frequency agile radios

using three main approaches:

Tunable PAs

Wideband PAs

Multi-band Pas

Accomplished Task:

Development of theoretical formulas to calculate and

plot the coverage of common tunable matching

networks on the Smith chart [2]


C1 C2

L

(a) (b) (c)

55

WP2: Frequency Agile Transmitter

Current Activities:

Design of Multi-band Power Amplifier operating at 0.8, 1.8, and 2.4 GHz.

The design uses a matching network optimized by a genetic algorithm.

Current Status: Design Completed. Waiting for fabricated prototypes to

start the measurements

Future Tasks:

Characterize varactor diodes (measure and de-embed)

Start the design of tunable power amplifier

Frequency (GHz)

Eff

icie

ncy (

%)

Ou

tpu

t P

ow

er

(dB

m)

FARAD56

WP3 Receiver Front End

Previous Tasks:1. Evaluation of LNA architectures for Multiband Blocker Resilient Operation between 400MHz and 6GHz

2. Evaluation of Blocker Filtering Techniques applied before LNA

3. Setup Testbenches for High Frequency Evaluation of LNAs

Outcomes:


1• Noise Cancelling Feed-Forward

Architecture was found to be best

suited for wideband operation [1]

2• Current best

implementations

use Frequency

Translation

Filtering [2]

• Q factor of

components is

translated to Low

Frequency

• Use of mixers

adds noise

• System Q still

limited by Low

Frequency Q of

filter components

3• Example results for UMC-L180-NMOS

L340nmW500u_33_RF with varying Vg

• Shows transistor Ft = 25GHz. Noise is nearly constant at HF.

[1] Bruccoleri, F., Klumperink, E. A. M., Nauta, B., & Member, S. (2004). Wide-Band CMOS Low-Noise Amplifier Exploiting Thermal Noise Cancelling, 39(2), 275–282.

[2] Hedayati, H., Aparin, V., & Entesari, K. (2014). A +22dBm IIP3 and 3.5dB NF wideband receiver with RF and baseband blocker filtering techniques. IEEE Symposium on VLSI Circuits, Digest

of Technical Papers, 1–2.

Gain Curves show transistor zero gain frequency varies

between 20GHz to 30GHz depending on biasing

1/f Noise

Noise stays nearly Constant

at Higher Frequencies

57

WP3 Receiver Front End

Current Activities:1. Evaluation of foundry PDKs for Cadence CMOS simulations

2. Advantages of using non 50Ohm Input Impedance

Future Tasks:• Evaluate possibility of using Active Filters before LNA for high Q narrow band filtering

• Complete Evaluation of IHP Foundry PDK and Plan for Tapeout

FARAD

1• Evaluation Completed:

AMS-S35D4(BiCMOS)

UMC-L180(180nm CMOS)

Results:

AMS process found to be

Unsuitable for 6GHz.

UMC RF transistors show

Ft=25GHz with acceptable noise

levels at high frequency operation

• Evaluation To Do:

IHP-SG25H3(250nm SiGe:C)

Outcomes:

2• Noise and Gain Circles for UMC-L180-NMOS L340nmW500u_33_RF transistor shows

wideband matching of noise and gain is possible by shifting input impedance above 50ohms

1dB NF Circles at:

400MHz

1GHz

6GHz

15dB Gain

Circles at:

400MHz

1GHz

3GHz

6GHz

Overlap region around

200ohm impedance

Gain Circle at

6GHz outside

overlap region.

Requires matching

circuit

58

Objective This workpackage focuses on the design of ADC Techniques and low PAPR

signal sets for concurrent multiband transmissions

Previous Activities:

Development of baseband modulator, demodulator and a digital down

converter (DDC) for a dual-band RF digitizing receiver test-bed through

LabVIEW and MATLAB [3]

WP4 A/D Conversion and PAPR Reduction


Fig. Block diagram of a dual-channel

reconfigurable digital receiver.

59

Fig. EVMrms(%) of QPSK and 16-QAM based single carrier signals over carrier aggregated

DTT and LTE bands received through RF digitising concurrent dual-band receiver.

60

Current Activities:

Study in to multi-band band pass sampling (BPS) techniques for direct RF

digitisation

BPS evaluation for a triple-band receiver, operating from 0.4 – 3 GHz RF

spectrum, through hardware testing with off-the-shelf ADC and comparison

against Nyquist sampling approach

WP4 A/D Conversion and PAPR Reduction


CA Scenario Total number of Combinations

Maximum AggregateBandwidth (MHz)

Minimum Sampling Frequency (MSPS)

(Lin’s Algorithm [4])

DTT – LTE(a) – Wi-Fi 288 61 213DTT – LTE(b) – Wi-Fi 384 101 337

DTT – LTE(a) – LTE(b) 1152 116 423LTE(a) – LTE(b) – Wi-Fi 768 130 414

Table: BPS analysis for CA scenarios for 0.4 – 6 GHz spectrum. LTE(a) corresponds to 0.7 – 0.96 GHz spectrum and

LTE(b) corresponds to 1.427 – 2.69 GHz spectrum. The 2.45 GHz Wi-Fi bands and TVWS (non-utilised DTT bands) in

Sheffield are considered.

Future Tasks:

BER/PER evaluation for dual and triple band test-beds

Design of a multi-band BPS ΣΔ ADC.

Study in to PAPR reduction techniques.

Academic Team



PI & Lead: Timothy O’Farrell

CoI: Richard Langley

CoI: Lee Ford

Ravinder Singh (WP 4 & 5)

Simon Bai (WP 1)


PI: Kevin Morris

PI: Mark Beach

CoI: Paul Warr

Chris Gamlath (WP 3)

Eyad Arabi (WP 2)

61

Industrial Partners


Questions

Thank you

Contact Details:

Professor Timothy O’Farrell


Department of Electronic and Electrical Engineering

Email: [email protected]

Professor Mark Beach


Electrical and Electronic Engineering Department

Email: [email protected]


mailto:[email protected]

References/Outputs

[1] Bai et. al, Tuneable Dual-band Antenna for Sub 1 GHz Cellular Mobile

Radio Applications, Submitted to “Loughborough Antennas and Propagation

Conference”, June, 2016.

[2] Arabi et. al, Analytical Formulas for the Coverage of Tunable Matching

Networks for Re-configurable Applications, Submitted to “IEEE Transactions on

Microwave Theory and Techniques”, March, 2016.

[3] Singh et. al, Demonstration of RF Digitising Concurrent Dual-Band

Receiver for Carrier Aggregation over TV White Spaces, Accepted for publication

at “IEEE VTC Fall”, May, 2016.

[4] Lin et. al, A New Iterative Algorithm for Finding the Minimum

Sampling Frequency of MultiBand Signals, “IEEE Transactions on Signal

Processing”, Vol. 58, No. 10, October 2010.

64

Slide 65 of 108

Low THz Technology and Applications

Mike Lancaster, Marina Gashinova and Peter Gardner

Department of Electronic, Electrical and Systems Engineering, The University of Birmingham

[email protected]; [email protected]; [email protected]


Slide 66 of 108

TRAVEL: Terahertz Technology for Future Road Vehicles

Peter Gardner

Dept of EESE, The University of Birmingham

[email protected]





Slide 67 of 108

TRAVEL: Progress to Date

• Propagation Measurements at 150 GHz and 300 GHz

• Novel broad band lens based antenna design for 300 GHz

• Experimental Radar designed for 670 GHz measurements

Slide 68 of 108

Aim and Objectives

Radome obstruction

Environmental contamination

Vehicle infrastructure

Atmospheric attenuation

Target

Reflectivities

Slide 69 of 108

Samples-Radome Obstruction

Road condition

Environment Vehicle infrastructure

1.1 Water 2.1 Non-painted plastic number plate with different thickness

1.2 Salty water 2.2 Coloured number plate with different paints

1.3 Road splash water 2.3 Head light

1.4 Ice 2.4 Car grilles

1.5 Snow 2.5 Bumper

1.6 Sand: dry and wet 2.6 Side mirrors

1.7 Grit 2.7 Windscreen

1.8 Dust

1.9 Soil: dry and wet

1.10 Dead insects

1.11 Leaves: dry and wet

1.12 Particulate contamination

1.13 Oil product

Slide 70 of 108

Pure Water Uniform Thickness

There is no dramatic difference in the transmissivity of

thin film water at automotive frequencies (24 and 77

GHz) and at low-THz frequencies (150 and 300 GHz)

Slide 71 of 108

Pure Water Droplets

Water droplets on the car

Averaging=20 Provided water droplets in our laboratory

Measurement Results

Slide 72 of 108

Fraunhofer Diffraction Theory

For U(n , m)=1 :

mn

mnN

n

M

m mn

mn

PR

jkR

r

jkrkajI

,

,

0 0 ,

,

2

2 expexp

4

2

mnr , = the distance between source point and each slit

mnR ,= the distance between observation point and each slit

Droplets U(n,m)= 0

Space U(n,m)= 1

Spaces: Max = 61.2 mm

Mean = 7.4 mm

Min = 0.19 mm

Droplet size: Max = 9.6 mm

Mean = 0.8 mm

Min = 0.06 mm

Slide 73 of 108

Simulation and Measurement of Transmissivity of Water Droplets

D=λ/2

Slide 74 of 108

Atmospheric Attenuation Measurements

15 m

Outdoor view

Cylinder

CR Sphere Cylinder

r = 180mm

σ = -10 dBsm

L = 100mm

σ = 21 dBsm

Indoor view

300 GHz

150 GHz

r = 200mm

h = 450 mm

σ = -70 dBsm

Slide 75 of 108

Effect of Water Droplets Formed on the Radome


mn

mnN

n

M

m mn

mn

PR

jkR

r

jkrkajI

,

,

0 0 ,

,

2

2 expexp

4

2

mnr ,= the distance between source point and each gap

mnR ,= the distance between observation point and each gap

Droplets U(n,m)= 0

Gaps U(n,m)= 1

Kirchhoff’s boundary condition:

a = size of gaps

Slide 76 of 108

Effect of Water Droplets Formed on the Radome


150 GHz 300 GHz

The captured photo from the droplets in this area

contain small droplet (about diameter of 0.06 mm)

which the used camera were not able to capture

them and results to the error about 4 dB.

Slide 77 of 108

Effect of Dry and Moist Sands on the Radome


Dry Sand at 150 GHz

Dry Sand at 300 GHz

3mm sand thickness with different moisture at 150GHz

0.5mm sand thickness with different moisture at 300GHz

0 5 10 15 20 25 30 35 40 45-25

-20

-15

-10

-5

0

Sand Thickness (mm)

Tra

nsm

issi

vity

(dB

)

Attenuation due to sand(Dry)

Attenuation Model

Natural Sand

Fraction A

Fraction B

Fraction C

Fraction D

Fraction E

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5-4

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

Sand Thickness (mm)

Tra

nsm

issi

vity

(dB

)

Attenuation due to sand(Dry)

Attenuation Model

Fraction D

Fraction E

0 2.5 5 7.5 10 12.5 15-30

-25

-20

-15

-10

-5

0Attenuation versus moisture with 3mm sand thickness

Moisture (vol.%)

Tra

nsm

issi

vity

(dB

)

Attenuation Model

Natural Sand

Fractiob C

Fraction D

Fraction E

0 2.5 5 7.5 10 12.5 15-16

-14

-12

-10

-8

-6

-4

-2

0

Moisture (vol.%)

Tra

nsm

issi

vity

(dB

)

Attenuation versus moisture with 0.5mm sand thickness

Attenuation Model

Fraction D

Fraction E

Slide 78 of 108

300 GHz fan beam antenna

Slide 79 of 108

150 GHz, 300 GHz & 670 GHz horn antennas

Slide 80 of 108

Broadband Waveguide Feed


Frequency,GHz

270 280 290 300 310

S1

1,d

B

-40

-30

-20

-10

0

Case A

Case B

Case C

Case D

Case E

D

L

εr

Extension layer

Hemisphere

Ground plane

Case A Case B Case C Case D Case E

No pocket z=0.1mm

x=wgx

y=wgy

z=0.3mm

x=wgx

y=wgy

z=0.2mm

x=wgx+0.2mm

y=wgy+0.2mm

z=0.2mm

x=wgx

y=wgy

x y

z

Slide 81 of 108

Tapered Extension Design


Alignment pins

Precision screws

θ

Frequency,GHz

270 280 290 300 310

Dir

ectivi

ty,d

Bi

26

27

28

29

30

31

32

33

o

Theta,degrees-50 -40 -30 -20 -10 0 10 20 30 40 50

No

rma

lize

d a

mplit

ude

,dB

-40

-30

-20

-10

0

Theta,degrees-50 -40 -30 -20 -10 0 10 20 30 40 50

No

rma

lize

d a

mplit

ude

,dB

-30

-25

-20

-15

-10

-5

0

f=290GHz:

E-plane H-plane

E-field plots

Slide 82 of 108

Lens prototype: Fabrication & Measurements


Frequency,GHz

282 284 286 288 290 292 294 296 298

Ga

in,d

B

22

24

26

28

30

32

34

Simulation tand=0.001

Simulation tand=0.008

Measurement Realized gain

Measurement Accepted gain

Frequency,GHz

220 240 260 280 300 320

S1

1,d

B

-35

-30

-25

-20

-15

-10

-5

0

Measurement

Simulation

Theta,degrees-20 -15 -10 -5 0 5 10 15 20

No

rma

lize

d A

mplit

ude

,dB

-40

-30

-20

-10

0

Theta,Degrees-20 -15 -10 -5 0 5 10 15 20

No

rma

lize

d A

mplit

ude

,dB

-40

-30

-20

-10

0

f=290GHz

H-plane

E-plane

Slide 83 of 108

300 GHz, S21 field

measurement

of snow in Scottish

Highlands using portable

VNA and Rubidium

reference.

Slide 84 of 108

Further Work


• Systematic attenuation and scattering measurements at 150 GHz, 300 GHz and 670 GHz

• Fan beam antenna and beamformer designs

• Proof of concept demonstrator

• Project runs until June 2018

Slide 85 of 108

Micromachined Circuits for THz Comms

Mike Lancaster


[email protected]


Slide 86 of 108

Micromachined Circuits For Terahertz Communications


EPSRC project EP/M016269/1

BAE Systems, Elite Antennas Ltd, Farran Technology Ltd, Plextek, Queen's University of Belfast, Teratech Components Ltd

With Rutherford Appleton Laboratory and Fraunhofer Institute

Slide 87 of 108

Micromachined 300 GHz Receiver


X3

XIF

47.5GHz

300GHz15GHz

142.5GHz

Configuration of whole system (based on 5 layers and each layer has the same thickness of 432µm)

47.5GHz LO WR-19 waveguide (4.775×2.388mm) Fed from base

15 GHz IF Fed from base

300GHz antenna

Slide 88 of 108

Resonator based design


x N

LO source

Multiplier Buffer

Multiplier

LO Spur BPF

Driver TX BPF

IF

TX PA

Waveguide Resonator

Two stage amplifier Mixer

Antenna

Multip

lier

No conventional on chip matching

Slide 89 of 108

Layers 1 and 2 hidden


Quartz substrate

E-field

MMIC amplifier

Frequency tripler (47.5 to 142.5GHz)

432um

WR-5 waveguide 140-220GHz 1.296×0.648mm

WR-3 waveguide 220-325GHz 0.864×0.432mm

300GHz antenna mixer

15 GHz IF

Slide 90 of 108

Micromachined Waveguides at 300 GHz


Waveguide

Filter

•WR3 waveguide size 864 m by 432 m

•Made of multiple layers

Half of a 300 GHz filter

E

Slide 91 of 108

Antenna


Various antenna developed (wideband high gain): • Dielectric lens • All resonator based waveguide slot antenna • Waveguide based conventional slot antenna • Metamaterial based planar antenna

Aperture antenna

based on all-resonator

stuctures

Feeding network based

on all-resonator

structures

Ē

Input Port

Radiating slots

Irises

H-plane bend and

matching ridge

Input port

1

d0

d

d0

a

a

b

b

l1

l2

Radiating waveguide

Feeding waveguide

x

y

z

xz-plane (H-plane)

yz-plane (E-plane)

d1

d2Layers

2

3

4

5

sw

sl

d01d02

Slide 92 of 108

Tripler

WF12 EPSRC Projects in Microwave, mm-wave and THz Research 92

• Tripler is based on all resonator structures.

• Diodes are coupled into the resonators

• The design removes any filtering and matching from

the microstrip (lossey) to waveguide

• 30 to 90 GHz demonstrated

Slide 93 of 108

Amplifier using coupled resonator filter based matching


Resonator 1 Resonator 2 Resonator 3

Screw

holePin hole

Iris

Input

Output

SMA Iris Iris

• Model of single waveguide input coaxial output completed at X-Band

• All resonator construction • Moving matching from PCB into

waveguide

Circuit Simulation Coupling Matrix

Measurements

Coupling Matrix

Circuit SimulationMeasurements

S21

S11

1 2 3 L S

Slide 94 of 108

Last words


• Three methods of fabrication:

• SU8 develop in EESE

• Collaboration with Mechanical Engineering on Laser machining

• CNC at RAL

• Good collaboration with RAL and Fraunhofer

• Good support from Terahertz advisory committee

Slide 95 of 108

PATHCAD: Pervasive low-TeraHz and Video Sensing for

Car Autonomy and Driver Assistance

Marina Gashinova


[email protected]


Slide 96 of 108

TASCC: Towards Autonomy - Smart

and Connected Control

A strategic partnership EPSRC Engineering and Information and Communication

Technologies (ICT) Themes in partnership with Jaguar Land Rover (JLR) initiated a

research in the area of 'Smart and Connected Control' around the central challenge of

moving towards a fully autonomous car.

PathCad project scope: Provision of all weather

sensing for driver assistance and ultimately

autonomous vehicle operation, through the

fusion of 3D low THz radar and video imagery.

Research challenges in Sensing:

• Robust sensor data fusion & which sensors to believe when they are giving conflicting information?

• All-weather and lighting and all-terrain capability

• Longer/wider range sensors & integration to V2X

• Optimisation – reduced number of sensors & required data stream

Slide 97 of 108

Technology areas:


• ‘Cross Learning’ to increase robustness of the

proposed system in all weather all terrains

• Novel THz sensors to deliver high resolution imaging.

• ‘Non-coherent interferometry’ to enable 3D

images that can highlight objects and act as an input to

the guidance and control system

• Advanced video analytics and sensors fusion with enhanced detection and classification of road users

Demonstrator

• Advanced signal processing - Azimuth refinement and

compressed sensing for ‘superresolution’

Slide 98 of 108

Why THz region?

• The frequency is high enough to produce a very fine resolution image and

• Low enough for the EM waves not to be dispersed due to precipitation, fog, dirt or any form of obstruction to the sensor

• Main drive to use these frequencies is small aperture sizes for a given angular resolution • High frequencies would bring the advantage of wide available bandwidths which results in fine range

resolution • Fine resolution achievable with moderate aperture sizes makes high resolution imaging feasible • Due to small wavelengths relative to the objects being imaged there will be more diffused scattering and

therefore imaging will be close to optical one. It could lead to high texture sensitivity

Frequencies between two absorption peaks • Due to attenuation of low-THz waves the sensing is feasible at

short-to-medium range depending on the operational medium

Slide 99 of 108

99

(degree)

(a) the image in Cartesian coordinatesR

ange (

m)

-10 -5 0 5 10

20

40

60

80

100

120

-40

-30

-20

-10

(degree)

(b) the image in polar coordinates

Range (

m)

-10 -5 0 5 10

20

40

60

80

100

120

-40

-30

-20

-10

(degree)

(c) the thresholding image in polar coordinates

Range (

m)

-10 -5 0 5 10

20

40

60

80

100

120

-30

-25

-20

-15

-10

(degree)

(d) the equalized image in polar coordinates

Range (

m)

-10 -5 0 5 10

20

40

60

80

100

120

0

0.2

0.4

0.6

0.8

1

(degree)

(a) the image in Cartesian coordinates

Range (

m)

-10 -5 0 5 10

20

40

60

80

100

120

-40

-30

-20

-10

(degree)

(b) the image in polar coordinates

Range (

m)

-10 -5 0 5 10

20

40

60

80

100

120

-40

-30

-20

-10

(degree)

(c) the thresholding image in polar coordinates

Range (

m)

-10 -5 0 5 10

20

40

60

80

100

120

-30

-25

-20

-15

-10

(degree)

(d) the equalized image in polar coordinates

Range (

m)

-10 -5 0 5 10

20

40

60

80

100

120

0

0.2

0.4

0.6

0.8

1

• Current automotive sensors are parametric sensors

• Current automotive radar demonstrate No imaging capabilities

while • Optical cameras are easily obstructed by any

form of dirt/mud/fog/spray, snow

The primary drive for using THz frequencies is aperture size and packing weight while maintaining fine range and angular resolution for high resolution imagery, compatible with optical imagery, in all weather/terrains

What to expect? Advancement to driving aid technologies

• Optical cameras are unable to provide a usable image in non-optically transparent media

94 GHz image map – previous research

Slide 100 of 108

Where we start. Critical mass of research/resources already done to support the proposal

150 GHz FMCW radar 300 GHz Up/Down Converter and antennas

15 °

2.2 °

x

y

z

Footprint

∞Axis of antenna beam

0 m min range

Elevation above ground

Microwave lens –horn antennas

-6 -4 -2 0 2 4 6

Ra

dia

l D

ista

nce [m

]

19.0

18.0

17.0

16.0

15.0

14.0

13.0

12.0

11.0

10.0

9.0

8.0

7.0

6.0

5.0

4.0

Filter Using Maxima nlfilter (Pre- thresholding on log data)

Azimuth distance [m]

Norm

alis

ed R

eceiv

ed P

ow

er

[dB

]

-22

-20

-18

-16

-14

-12

-10

-8

-6

-4

-2

0

150 GHz image of road markings

Previous EPSRC funding and direct industrial funding (JLR) on THz sensing and imaging

Slide 101 of 108

Where we are now – 6 months after the project start

Scene actor identification from video, IR and LiDAR data

Gap analysis of existing sensor suit and preliminary data collection

Roof railway for experimentation under controlled motion

Synchronization of Radar Video/Stereo camera/ LIDAR Radar angular resolution refinement

Slide 102 of 108

150 GHz Radar Experimental Equipment

• Antennas

– 2° x 15° lens horn

• Data Acquisition

– FFT (magnitude) outputs for up and down sweep (Ethernet/UDP)

– I/Q (and Strobe) recording through PicoScope

Parameter Value

Centre Frequency 148 GHz

Bandwidth 6 GHz

Range Resolution 2.5 cm

Power 15 mW (12 dBm)

Modulation FM Linear Up/Down Chirp

Sweep time 1, 2, 5, 10 ms

Picoscope 5000 Series USB Oscilloscope

Slide 103 of 108

-6 -4 -2 0 2 4 6 8

15.0

14.0

13.0

Radi

al D

ista

nce

[m]12.0

11.0

10.0

9.0

8.0

7.0

6.0

5.0

4.0

No Filter (Pre-thresholding on log data)

Azimuth distance [m]

Norm

alis

ed R

eceiv

ed P

ow

er

[dB

]

-30

-25

-20

-15

-10

-5

150 GHz Image 30 GHz Image

-5 0 5

2

4

6

8

10

12

14

16

18

Azimuth Distance (m)

Range (

m)

No Filter (Pre-thresholding on log data)

Norm

alis

ed R

eceiv

ed P

ow

er

[dB

]

-30

-25

-20

-15

-10

-5

footpath

0 m

Sensitivity to roughness/texture

Slide 104 of 108

Radar video – Laboratory ‘Road’ Scene Data Collection

• First radar video created in laboratory conditions with road scene actors

– Radar is translated linearly alongside typical ‘critical area’ scene and also scanned in azimuth

– Video now produced in equivalent time of previous single scans

Laboratory Based ‘Road’ Scene

2 m Linear Positioner Rail Radar Linear Translation

Scan

Radar

Speed Bump

Cycle Pedestrian

Trolley

Road Signage

Kerb Stones

Metal Sphere

Slide 105 of 108

Laboratory Radar Video

Velodyne (32 beam)

ZED stereo camera Kinect Attached to the top of radar

Slide 106 of 108

Multi-sensor Acquisition

• Measurement of calibration/registration targets

• Corner reflectors of differing sizes

• Measured in two positions on short linear rail

Velodyne

Kinect

Radar

Slide 107 of 108

Conclusions and Plans

• Addressing shortcomings of currently available sensor systems to respond to the

future trends as well as the fundamental problem of efficient resource and

information utilization.

• Impact of the resulting system can encompass many applications where imaging will be crucial, including the development of effective instruments for aerial vehicle automatic landing aids, missile guidance, covert detection of hidden weapons on humans, in robotic imaging and navigation, and even soil assessment and crop quantification by agricultural robotic vehicles.

• We welcome discussion with international research communities working in a

number of fields related to the project. These fields include radar, signal

processing, vision systems, machine learning.

• Academic and industrial communities from both the defence and civilian sectors

can follow our progress through the web-site

• Towards the end of year 4 we plan a workshop in Birmingham that will address Sensing for Autonomous Vehicles. By this stage we will have video footage from trials that will demonstrate in a clear way the potential capability of our sensing system to both specialists and non-specialists. A number of companies, with interests in all-weather sensing, from both the civilian and defence sectors will be encouraged to attend.

Slide 108 of 108

Open Discussion and Concluding Remarks

Peter Gardner

University of Birmingham

[email protected]


Documents

EPSRC Projects in Microwave, Millimetre-Wave and THz Research · M1. Demonstration of devices with switching time < 10 ns M2. Demonstration of a high-speed buck converter MMIC –