A new design of an active antenna with a dielectric resonator stabilized high electron mobility transistor (HEMT) oscillator (DRO) and an aperture-coupled patch antenna is reported. The circuit is fabricated using coplanar waveguide (CPW) with the oscillator and the antenna on opposite sides of the substrate. The active antenna was demonstrated at 7.6 GHz; however, the design can be scaled to higher frequencies. Excellent oscillator characteristics and radiation patterns were obtained

Lee, Richard Q.

Simons, Rainee N.

English

NASA Technical Reports Server

Plamr Dielectric Resonator S h i h e d  &E%@'I' 
Oscillator kitegrated With CPW/Aperture 
Coupled Patch Antenna 
Rainee N. Simons 
S v d r u p  Technology, Im. 
Lewis Resemk Center G m p  
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Prepared for the 
1992 iEEE MIT-S h t d d  Mmwave Spposium 
ATbkqserque, New W c o ,  June 2 -4,lW. 
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https://ntrs.nasa.gov/search.jsp?R=19920009231 2020-03-17T12:33:22+00:00Z
PLANAR D~ELECTRIC RESOPJATOR !iTABILIZED H E M  OSCILLATOR 
INTEGRATED WITH CPWIAPERTURE COUPLED PATCH ANTENNA 
Ralnec N. Simons and Richard Q. Lee 
National Aeronautics and Space Administration 
LCV~IS Research Center 
Cleveland. Ohio 44 135 
Abstract the transmission line coupled to the dielectric nsonator respec- 
tively. r ts wrinu, d I 
A new &sign o f  an active antenna with a dielectric resona- 
tor stabilized HEMT oscillator (DRO) and an qc~u rc -coupkd  rc = s,, + ~ ~ & ~ r ~  a ( 1  - s?~I-~) - ' .  (1) 
patch antenna 1s reported. The circuit is fabricated using coplanar 
waveguide (CPW) with the oscillator and the antenno on opposite 
sides of the substrate. The active antenna war demonstrated at Where SLI, SIZ. S?,, and &2 arr: the scattering parameters o f  the 
7.6 GHz; however, the design can be scaled to higher frequencies. HEMT with a trsnsmiwion line o f  length d, connected in series 
Excellent oscillator characteristics h d  radiation pPncm have been with the source to pmvi& feedback. and T, is the reflection cod- 
obtained. ficient o f  the load connected to the drain. T, is written as 
As thc frequency of operation o f  htth observation systems 
(EOS) shifts into the millimeter wave and submillimeter wave 
regioru of the spactrum, them is a need to develop efficient power 
combining techniques which can eliminate ciwuit losses, minimize 
expensive machining o f  mounts and housing for diodes, reduce 
thermal problems, provide graceful degdation and combine large 
number o f  active devices. Conventional low frequency power 
combining techniques a n  unable ro m e t  the above requirements, 
and hence quasi-optical or spatial power combining have to be 
employed. I n  the past, a quasi-optical integrated antenna and 
receiver front end was demonstrated using MESFET oscillator 
coupled to a slo:lrnesoplanar waveguide antenna.' A wideband 
tunable active antenna and power combiner war also demonstrated 
rvrng a Gynn diode mounted in a rlotlinesoplanar waveguide 
6 esonator.- 
In this paper, we demonstrate a new design of an active 
antenna module with a dielectric resonator stabilized HEMT oscil- 
lator (DRO) which is apemre-coupled to a patch. Several o f  these 
modular antennas can be combined to form a spatial power corn- 
I biner. The circuit IS fabricated using coplanar waveguide (CPW) 
t w ~ t h  the oscillator and the patch antenna on opposite sides o f  a 
twwlayer dielectric substrate. By fabricating the,antenna m d  the 
oscdlator on two substrates o f  different pemittiviiy and ~h~ckness. 
J both o f  these components can be independently optimized for best 
performance. 
t 
11. &sign Descrivtion and Fabrication 
Oscillator 
Figure I shows the schematic of a DRO with stria f a d -  
back. In this circuit and rr a n  the reflection coefficiert look- 
ing into the gate terminal o f  the HEMT and the input terminal o f  
r, = rC exp - j  2 . [ ?;) 
Whtm r, is the mf l~c t ion  coefficient at the reference plane of the 
resonator which is at a distance d from the gate. I', lakes into 
account LIIC coupling coefficient $and the termrnatton &. The 
condition for r d y  state oscillation to occur in the crrcurt can be 
written as3 
To fabricate the oscillator, the kngth d, which provid'ts the 
series feedback is adjusted so that the HEMT is unstable, :k. ; i:, 
should be greater than untty. The location $ of the ditlec- 
tric resonator with respect to the gate IS adjusted so as to satlofy 
Eq. (3). The CPW circuit layout fo: the w i l l a to r  part of the 
active antenna is shown in  Fig. 2. The circuit is fabricated on 
0.635 mm thick RT/Dumid 6010.5. Tile actrve devlce IS a lo* 
noise HEMT (Model SS902) manufactured by Toshrba. Thc J ~ c l w -  
tric resonator (Part no. TC-8500-x-001) is man~factured by Trdnc- 
Tech. lnc. 
Antenna 
Figure 3 illustrates the CPW apenure-coupled pntch nnlennil 
part o f  the active antenna. The coupling takes place through an 
apeflure in  thc common ground plane separating the CPW and the 
patch. The aperture width W2 of  0.254 tnm is chosen for ease o f  
fnbrication. A good inilial guess Ibr the aperture length I? 1s 
AR(ddlulc,E, where A is the wavelength of an uniform slotl~ne. 
This starting value 0th is then slightly rcduced ta account for the 
slot end effects. To  improve coupling a notch of width W', 
(0.75 mm) and length LI is cut out from the CPW ground plane 
!oca~ed right above the aperture. The longitudinal distance 
betweon the extreme ends of the notches is slightly less than the 
aperture length 4. The CPW is terminated in a short circuit at a 
distance of approximately Aercpwf2 from l e  center of the notch. 
The lengrh A of the patch is ksr dun half wavelength after cor- 
recting for end effectr. The width B of the patch is 1.5 timer A. 
To improve couplinp, La; apertum is off- by atout 5.5 mm f s m  
the center of the patch. The teed and the patch ue fabricated on 
0 9 8  and 0.254 mm thick RT/Dumid 5880 rebpectivdy. 
Ill. Expenmental Results and Discussions 
-- 
The m u s u d  frequency spectrum at 7.6 GHz of the active 
antenna is shown in  Fig. 4. The stnbility of oscillations is excel- 
lent. The measured H-plane mdiation pattern of the active antenna 
is shown in Fig. 5 and is observed to be typical of a patch. The 
m e m u d  cross-polarization is leu than -20 dB. By substituting 
the mawred power and gain into the Friis tranamiorion fonnula 
the absolute power radiated by the patch antenna is &ermined to 
be I. 1 mW. This is small since the HEMT is a low-noise low- 
power device. 
IV. Conclusions 
pmmted. Although the ~ t i v e  antem is damonstrated at 
7.6 GHz, the dsrign can be easily ralad to higher frequencies. 
Excellent o~ci lhtor charactcridics and radiation pattern have been 
obtained. 
1. V.D. Hwang, T. Uwano. and T. Itoh. nQW+~pt i~a l  integrated 
antenna md receiver front end," IEEE Trans. Microwave 
Theow Tech., vol. 36. pp. 80-85. 1988. 
2. J.A. Navarm, Y.H. Shu, and K. Chang, *Wideband integrated 
varactor-tunable active notch antennas and power combin- 
en." IEEE MIT-S International Microwave Symposium 
New Yo*: IEEE, 199 1, vol. 3. pp. 1257- 1260. 
3. G.D. Vendelin, A.M. hvio, and U.L. Rohde, Microwave Cir- 
:uit Desinn Using Linear and Nonlinear Tschniquea. 
New York: John W i l q  & Sons, 1990. Chap. 6. 
An active antenna with a dielectric resonator stabilized 
HEMT oscillator and a CPWiaperture coupled patch antenna is 
Figure 1 .-Schdmatk of a dielectric resonetor 8tabi l i i  HEMT 
oscillator with aeries f e e d k k  
L T o  antenna 
Figun 2.--CPW circuit for the aecillator part of the active 
antenna. 
Figure 3.--Schemati illustrating the CPW aperture-coupled 
patch antenna part of the active antenna. 
FIgum,4.--M~red frsquency spectrum of the oscillator. 
Center freqwncy b 7.6 GHt, Rer. BW = 100 kHz, Hor. div 
= 1 MHz, Ver. dk - 10 dB. 
Figure 5.--Mewred far field H-plane radkition pattern of the 
active antenna. 
REPORT DOCUMENTATION PAGE Form Approved OMB NO. 07M-0188 
- 
1. AGENCY USE ONLY (Leave blank) 1 2 REPOnT DATE 1 3. REPORT TYPE AND DATES COVERED 
I 1992 I Technical Memorandum 
4. TITLE AND SUBTITLE 5. FUNDING NUMBERS 
Planar Dielectric Resonator Stabilized HEMT Oscillator Integrated 
With CPW/Apeiture Coupled Patch Antenna 
Rainee N. Simons and Richard Q. Lee 
tiational Aeronautics and Space Administration 
Lewis Research Center 
Cleveland. Ohio 44 135 - 3 19 1 
,- 
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 
9. SPONYoRINGjMOWToRlNG AGENCY NAMES(S) AND ADDRESS(ES) 
8. PERFORMING ORGANIZATION 
REPORT NUMBER 
National Aeronautics and Space Administration 
Washington, D.C. 20546- 0001 
10. SPONSORlNG/MONlTORlNG 
AGENCY REPORT NUMBER 
NASA TM - 105544 
I 
11. SUPPLEMENTARY NOTES 
Prepared for the 1992 IEEE MIT-S International Microwave Symposium, Albuquerque, New Mexico, June 2-4, 1992 Rainee N. S~rnons. 
Svcrdrup Technology, Inc., Lewis Research Center Group. 2001 Aermpace Parkwa). Brook Park Ohio 44142 (work funded by NASA Contract 
NAS3-25266); and Richard Q Lee, NASA Lewis Research Center. Respoosible person Richard Q Lee. (2 16) 433- 3462 
Unclassified -Unlimited 
Subject Category 33 
-- - 
I 
13. ABSTRACT (Mnxlmum 2M w r d s )  
120. DISlWBUTK)N/AVAILABlLITY STATEMENT 
A new design of an active antenna with a dielectric resonator stabilized HEMT oscillator (DRC") and an aperture- 
coupled patch antenna is reported. The circuit is fabricated using coplanar waveguide (CPW) with the oscillator and 
h e  antenna on opposite sides of the substrate. The active antenna was demonstrated at 7.6 GHz; however, the des ip  
can be scaled to higher frequencies. Excellent oscillator characteristics and rddiation pattern have been obtained. 
12b. DISTRIBUTION CODE 
14. SUBJECT TERMS 
Dielectric resonator; HEMT oscillator; Patch antenna; Aperature 
I 
L NSN 7540-01-280-5500 
B 
coupling; Coplanar waveguide 
- 
19. SECURITY CLASSlFlCAtKWl 20. LIMITATION OF ABSTRACT L OF ABmACT Unclassified 7 L 
Standard Form 298 (Rev. 2-89) 
Pre.mibd by ANSI SId. 239-18 
298-1 02 
17. SECWITY CLASSFlCATION 
OF REPORT 
Unclas3ified 
18. SECURITY CUSStFlCATION 
OF THIS PAGE 
Unclassified 


Planar dielectric resonator stabilized HEMT oscillator integrated with CPW/aperture coupled patch antenna

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