-
Abstract
This paper presents the study, design, fabrication of 4 - way
Wilkinson power divider to be used for the microwave
power transmission system at S band. The Wilkinson power divider
divides the signal from the oscillator is 4 - way the
equal amplitude and phase before send to the power amplifier.
The design and simulated results have been carried out
by ADS2009 package - the professional design software for
microwave engineering. The experimental results
demonstrate the ability in broadband applications and relevance
of the power divider for the microwave power
transmission at S band. All simulations and measure results will
be reported.
THIT K CH TO B CHIA CNG SUT KIU CU WILKINSON
TRONG H THNG TRUYN NNG LNG KHNG DY BNG TN S
ThS. on Hu Chc, KS. Nguyn Th Hng
Khoa in - in t, Trng i Hc Dn Lp Hi Phng
I. Gii thiu
ic khuch i tn hiu c cng sut ln bng
tn S gp rt nhiu kh khn. V vy chng ta
thng thc hin bng cch s dng nhiu b khuch i
cng sut c cng sut ra nh hn ri sau mi kt hp
li t cng sut mong i. Mun thc hin iu ny
ngi ta nghin cu cc k thut chia v cng cng
sut. Hnh 1 m t mt h thng pht cng sut ln s
dng cho vic truyn thng tin hoc nng lng khng
dy s dng cc b chia/cng cng sut. Do b
chia/cng cng sut l mt thnh phn ca h thng siu
cao tn v n c nhim v chia/cng cng sut tn hiu li
vo thnh nhiu tn hiu li ra ng pha hoc ngc li.
V
B chia
cng
sut
1:4
B
cng
cng
sut
4:1
Ngun DC
OSC
BUF
PA
PA
PA
PA
Hnh 1. Cu trc h thng pht nng lng khng dy
OSC: Osccilator;
BUF: Buffer Amplifier ;
PA: Power Amplifier .
Trong thc t, b chia/cng cng sut kiu cu
Wilkinson hay c dng nht bi y l cu trc c c
tnh khng tn hao nu nh tt c cc cng li ra u c
phi hp tr khng vi li vo v s cch ly gia cc cng
rt tt. E.J. Wilkinson l ngi pht trin b chia ny
nn b chia/cng c t theo tn ng. B chia/cng
cng sut WPD l mt phng php chia cng sut ng
pha v ng bin .
B chia WPD c s l b chia hai. B chia ny s
dng on dy /4 ti trung tm tn s thit k vi hai
nhnh chia cng sut c tr khng c tnh l v mt
in tr 2*Z ni hai cng ra vi nhau. Cu trc ca b 0
chia WPD 1:2 s dng k thut mch di c cho
hnh 2.
Hnh 2. B chia cng sut Wilkinson 1:2.
B chia WPD c tt c cc cng ra u c phi hp
tr khng 50 v cch ly gia cc li ra vi nhau nhng n
cng b suy hao. Ma trn tn x b chia WPD 1:2 c
a ra cng thc sau:
a.Cu trc dng mch di
b. S mch tng ng
(1)
22 Bn tin Khoa hc - o to
Hot ng nghin cu khoa hcHot ng nghin cu khoa hc
-
Ch rng khi cc cng ra u c phi hp tr
khng (S =0) vi li vo th chng ta c:11
Chng ta s xy dng c b chia WPD 1:4 bng
cch mc ghp ni tng cc b chia WPD 1:2. Trong
trng hp b chia WPD 1:4 ta c ma trn tn x nh sau:
(2)
0 / 2 / 2 / 2 / 2
/ 2 0 0 0 0
/ 2 0 0 0 0
/ 2 0 0 0 0
/ 2 0 0 0 0
j j j j
j
j
j
j
(3)
Ta cng c:
(4)
Trong khun kh bi bo ny trnh by vic m
phng, thit k v ch to mch chia cng sut Wilkinson
4 cng cng nh cc kt qu m phng v thc nghim.
II. Thit k m phng mch chia cng sut Wilkinson
2.1. Thit k m phng mch
B chia cng sut Wilkinson 1:4 c m phng, thit
k bng phn mm ADS2009. Trong trng hp ny b
chia c thit k hot ng trong di bng tn S. S
nguyn l c cho hnh 3.
Hnh 3. S nguyn l mch chia cng sut Wilkinson.
Kt qu m phng cc tham s S11, S21 v S cho 23
trn hnh 4.
Hnh 4. Kt qu m phng b chia cng sut Wilkinson 1:4.
Theo gi tr m phng S =-6.01dB, S = -41dB v 21 11
S =-45dB ti tn s 2,5GHz.23
2.2. Kt qu thc nghim
T s nguyn l ta thc hin thit k mch in nh
phn mm ADS2009. S mch in v sn phm thc t
c cho trn hnh 5. Mch in c dng ng cong nhm
mc ch lm gim kch thc ca mch in v s ghp
ni gia cc cng ra vi nhau.
Hnh 5: B chia cng sut Wilkinson 1:4.
S dng my phn tch mng tin hnh o cc tham
s S v S ca mch ta c kt qu nh hnh 6 v 7. 21 31
a. S mch in b. Sn phm thc t
Hnh 6. Tham s S o c trn my phn tch mng21
23
Hot ng nghin cu khoa hcHot ng nghin cu khoa hc
-
Hnh 7. Tham s S o c trn my phn tch mng.31
S =-5.985 v S =-5.886 l nhng gi tr tt hn c 21 31
mong i khi so snh vi kt qu t c trong m
phng hnh 4.
Cc tham s S , S v S c cho trn cc hnh 11 22 33
8,9,10.
Tham s S c cho trn hnh 11. Theo S = -23 23
22.3dB ti tn s f= 2.5GHz.
Hnh 10. Tham s S o c trn my phn tch mng.33
Hnh 9. Tham s S o c trn my phn tch mng22
Hnh 8. Tham s S o c trn my phn tch mng.11
Hnh 11. Tham s S o c trn my phn tch mng.23
III. Kt lun
B chia/cng vi h s chia 4 kiu cu Wilkinson c
tnh i xng to c cc dao ng ng pha v ng
bin trn c s t mt b dao ng OSC. B chia
c ch to chia ra 4 ng a ti cc b khuch i
cng sut PA. B chia/cng ny p ng y cc yu
cu chia ng pha v ng bin b.
TI LIU THAM KHO
[1] David M.Pozar, Microwave Engineering,
John Willey & Son, INC, Second Editon;
[2] Dang Thi Thanh Thuy, Nguyen Dinh The Anh
and Bach Gia Duong Study, design and fabrication of
a high-power combiner using 8-way Wilkinson Bridge
for a transmitter system of an L-band, VNU Journal
of Science, Mathematics Physics 27, No. 1S (2011)
239-242.
[3] Taufiqqurrachman, Deni Permana Kurniadi,
Design and Realization Wilkinson Power Divider at
Frequency 2400MHz for Radar S-Band, IOSR
Journal of Electronics and Communication
Engineering (IOSR-JECE), Volume 3, Issue 6 (Nov. -
Dec. 2012), PP 26-30;
[4] A. Wentzel, V. Subramanian, A. Sayed, and G.
Boeck, Novel Broadband Wilkinson Power
Combiner, Proceedings of the 36th European
Microwave Conference, pp. 212- 215, 2006.
[5] E. J. Wilkinson, An N-way hybrid power
divider, IRE Trans. Microwave Theory Tech., vol.
MTT8, pp. 116118, Jan. 1960.
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