A SMALL COUPLE SLOTTED ANTENNA FOR

UWB APPLICATION

(Yusnita Rahayu, Tharek A.Rahman, Razali Ngah)

978-1-4244-4076,2009,IEEE

Presented by:

JIGYASA SINGH

M.TECH(ECE)

Introduction

• WPAN technology aims to provide a reliable wireless communication between computer, portable devices & consumer electronics within short range.

• This requires high data rate.

• Therefore, UWB technology has been designed & developed to meet this demand.

• For this, UWB antennas are essential.

Features

• Uses a couple of L and U slot.

• Truncated ground plane is used to control antenna impedencematching.

• Fed by microstrip line, alignment error results in degradation of antenna performance.

• Dimension- 30mm x 30mm.

Geometry of L and U couple slotted antenna

The pentagonal antenna isvertically installed above aground plane (lgrd) of 11 mm. Theoptimum feed gap (h) to theground plane is found to be 1.5mm. The dimension of substrateis chosen to be 30 x 30 mm2 (Wsub

x Lsub). Antenna has a pentagonalpatch with a width (w) of 15 mmand a length (l) of 12 mm.

Why & How?

• UWB range- 3.1 Ghz to 10.6 Ghz, this antenna is giving a omnidirectional pattern over this range.

• Good return loss with respect to -10 db.

• These slots are designed investigating the behaviour of current flow distribution of patch antenna.

Factors choosing antenna topology

• Physical profile.

• Compatibility.

• Impedence.

• Radiation efficiency.

• Radiation pattern.

L slot & U slot

• Length of L slot = 14.5 mm approx. equal to 0.25λ at 5.3 Ghz.

• Length of U slot = 11.5 mm approx. equal to 0.4λ at 10.3 Ghz.

• L slot = improves lower dip resonance.

• U slot = improves upper dip resonance.

• L SLOT + U SLOT = GOOD RETURN LOSS at -10 db.

Measured & simulated return loss for L & U couple slotted antenna.

E plane & H plane

• Simulated & measured E & H plane for 4 Ghz & 5.8 Ghz.

• H plane shows good-omnidirectional pattern for both frequency range.

• E plane shows broad & slight distorted & slightly distorted at 5.8 Ghz.

Measured & simulated radiation pattern for L & U slotted antenna.

Working

• Current distribution is simulated by using Zeland FDTD simulation software.

• Current along the edges introduces a additional resonance + resonance of the main patch = broadband frequency characterstic.

Conclusion

• A small couple slotted of L and U antenna has been presented.

• This antenna uses two coupling slots with a partial ground plane for bandwidth enhancement.

• An experimental prototype has been designed, fabricated and tested.

• The measured return losses cover the UWB bandwidth requirements of 2.5 GHz –10.1 GHz with respect to -10 dB.

• The measured radiation patterns of this prototype are also presented at frequencies 4, and 5.8 GHz, respectively.

Future Work

• From the graph we saw that E plane shows slightly distorted radiation pattern.

• The improvement can be achieved by cutting out the edges of the finite ground plane.

• This produces a phase shift between the induced equivalent magnetic currents on the edges, thereby causing cancellation in the diffracted fields.

• We can numerically and experimentally examined the effects for some patch antennas and confirmed that the distortions in E plane pattern could be eliminated by using this approach.