NASA Technical Memorandum 107136

Finite Width Coplanar Waveguide Patch Antenna

With Vertical Fed Through Interconnect

Rainee N. Simons

NYMA Inc.

Brook Park, Ohio

Richard Q. Lee and Kurt A. Shalkhauser

Lewis Research Center

Cleveland, Ohio

Jonathan Owens, James Demarco, Joan Leen, and Dana Sturzebecher

PSD, Army Research Laboratory, AMSRL-PS-E

Fort Monmouth, New Jersey

Prepared for the

1996 IEEE AP-S International Symposium and URSI Radio Science Meeting

cosponsored by IEEE, AP-S, and U.R.S.I.

Baltimore, Maryland, July 16-21, 1996

National Aeronautics and

Space Administration
Trade names or manufacturers' names are used in this report for identification

only. This usage does not constitute an official endorsement, either expressed

or implied, by the National Aeronautics and Space Administration.
FINITE WIDTH COPLANAR WAVEGUIDE PATCH ANTENNA

WITH VERTICAL FED THROUGH INTERCONNECT

Rainee N. Simons', Richard Q. Lee e, Kurt A. Shalkhauser °

"NASA Lewis Research Center Nyma Group, o NASA Lewis Research Center,

21000 Brookpark Road, Cleveland, Ohio 44135

Jonathan Owens, James Demarco, Joan Leen

and Dana Sturzebecher

PSD, Army Research Laboratory (ARL), AMSRL-PS-E, Fort Monmouth,

New Jersey 07703

Abstract

The paper presents the design, fabrication and characterization of a finite

width coplanar waveguide (FCPW) patch antenna and a FCPW-to-FCPW vertical

interconnect. The experimental results demonstrate the antenna and interconnect

performance. A scheme to integrate an eight element FCPW patch array with

MMIC phase shifters and amplifiers using vertical interconnects is described.

The antenna module has potential applications in an advanced satellite to ground

transmit phased array at K-Band.

I. INTRODUCTION:

A Finite Width Coplanar Waveguide (FCPW) on a dielectric substrate

consists of a center strip conductor separated from finite ground planes by

narrow slots on either sides [1] as shown in Fig. 1. The substrate thickness, the

strip width, the slot width and the ground plane width are denoted as D, S, W and

G respectively. The FCPW has all the advantages of conventional CPW [2] and in

addition the finite ground planes suppress, the propagation of spurious substrate

modes. The spurious substrate modes at high frequencies can degrade the

electrical performance of an array antenna. In the past several authors [3], [4]

have investigated conventional CPW patch antennas at 4.3 GHz and 8.5 GHz

respectively fabricated on a low dielectric constant substrate, _r _-" 2.2. This

paper discusses first, the design, fabrication and experimental characterization

of a FCPW patch antenna with an integrated feed at K-Band. The width of the CPW

ground planes are arbitrarily taken as twice the center strip conductor width

which results in a very compact feed design. The entire circuit is fabricated on a

low temperature co-firing ceramic tape (Ferro Corp.), _r = 5.9. The higher

dielectric constant of the substrate material helps to reduce the size of the patch

which results in a compact array. The conductor pattern is deposited using gold

paste and low cost screen printing technique. Second, the measured performance

of a FCPW-to-FCPW vertical fed through interconnect is presented. Lastly, the

vertical integration of an eight element FCPW patch array with a system level

integrated circuit (SLIC) module consisting of MMIC phase shifters and

amplifiers is described. The resulting tile subarray has potential applications in

an advanced satellite to ground transmit phased array.
II. INTEGRATED F_E_CPWPATCH ANTENNA:

a.) Construction:

A schematic illustrating the integrated FCPW patch antenna is shown in

Fig. 1. The antenna is constructed by widening the center strip conductor of the

FCPW to form a rectangular patch. The lowest order of resonance for the patch

occurs when the mean slot length summation a-thru-i is one guide wavelength

_,g(s_otl.At resonance the electric field lines are as shown in Fig. 1. The antenna

radiates with a polarization parallel to the side c-d or f-g.

b.) Measured Characteristics:

The input impedance of the antenna is determined using THRU-REFLECTLINE on-wafer calibration standards, a pair of G-S-G microwave probes,

HP8510C ANA and NIST De-embedding software [5]. The TRL standards are also

fabricated on the same substrate as the antenna using the screen printing

process. The experimentally de-embedded input impedance at the reference plane

P-Q is shown in Fig. 2. The antenna resonates at about 19.95 GHz. The measured

E-and H-Plane radiation patterns, gain and the cross-polarization level will be

discussed at the conference.

III. FCPW-to-FCPW VERTICAL INTERCONNECT:

A schematic illustrating two back-to-back FCPW-to-FCPW vertical

interconnect with a short length of FCPW in between is shown in Fig. 3. The via

has a diameter of about 0.01 inch. The rest of the dimensions are same as in

Fig. 1. The measured return loss and insertion loss are shown in Fig. 4. These

measurements show that, the insertion loss and return loss per interconnect is

about 0.3 dB and -30 dB respectively.

IV. INTEGRATION OF ANTENNA OVERLAY WITH SLIC MODULE:

The SLIC module is being developed by Lockheed Martin under a contract

from NASA Lewis Research Center. The module consists of four dual channel MMICs

with supporting circuitry. Each of the dual channels consists of a 3-bit phase shifter,

an analog attenuator and amplitude calibration and control elements. In addition, the

module also has a photonic link to bring the 20 GHz RF signals and digital control

signals. A second link returns module status to the controller. Fig. 5 schematically

illustrates the integration of the antenna overlay with the SLIC module. The results of

the overlay characterization will be presented at the conference.

REFERENCES

[1] R.N. Simons and R.Q. Lee, "Coplanar Waveguide Aperture Coupled Patch

Antennas with Ground Plane/Substrate of Finite Extent," Electron. Lett., Vol.

28, No. 1, pp. 75-76, Jan. 1992.

[2] K.C. Gupta, R. Garg and I.J. Bahl, Microstrip Lines and Slotlines, Dedham, MA:

Artech House, 1979, Chap. 7 on Coplanar Lines.

[3] J.Wo Greiser, "Coplanar Stripline Antenna," Microwave Journal, Vol. 19, No. 10,

pp. 47-49, Oct. 1976.

[4] Ho-C. Liu, T.-S. Horng and N.G. Alexopoulos, "Radiation of Printed

Antennas with a Coplanar Waveguide Feed," IEEE Trans. Antennas and Prop.,

Vol. 43, No. 10, pp. 1143-1148, Oct. 1995.

[5] NIST De-embedding Software, Program DEEMBED, Revision 4.04, 1994.

2
/- De-embedding

reference plane

p---- Q

 tsl-

_,- E-field

... ,. ,/// .,, , . ,_.'.,. _.;, /

,.+'?"i....;>........ ,.,_<:..s........ " ->......_77: ::;........

Ground _/ ......-"--"- "_.,.,: .......... / /_ - -

conouctors-_---____-'_; "_. ...,-"_L. ..- - j" i- i - "

....... _T-__, _., /_" _--.s'": _ _'_,

Strip iI_ _ J / _- NO ground

conductor J _ plane

Figure 1 .---Schematic of FCPW patch antenna. _r = 5.9, D = 0.01125 in., S = 0.012 in., W = 0.004 in. and G = 0.024 in.

$11 REF 1.0 unitsZ

200 mU_ "i/iiI.I_:___

I ' " _.--""_I_. ,// "J

t ',

\ \ /_- \ i'/ I iii 53411 \=o,:,,.- ,>-._- >:/

Figure 2.--Measured input impedance of the antenna.
/ .//" /1"_1

FCPW--. /'_/ // /

/_vJ>//_/_//// / / / _ planeN° ground

Figure 3.--Schematic of two back-to-back FCPW-to-FCPW vertical interconnect.

D = 0.01125 inch, e.r = 5.9.

0 --

-10

_ ,- -20

rr -30

-40 I I 1 I I I I I I I

15 16 17 18 19 20 21 22 23 24 25

Frequency, GHz

o, \

-- _ -1 _

,-no

._o

15 16 17 18 19 20 21 22 23 24 25

Frequency, GHz

Figure 4.--Measured retum loss and insertion loss of the interconnect.

Location of

patch antenna_ / _

Antenna MMIC phase

oveday_ / X X fJ shifter &

_Af X - " _/__ attenuator_ - Photo

.... _._%'-_/_--- vemcaJ .-_....-_c <_ / ,_ FCPW patch _ _-_ intAmnnn_r_.t circuits --\// _

antenna j- _ _,1_1_,_ "_ ............ j,_ .'-_ _ /_'_

"__ Gold bumps I__ _ _'_" "

_DC bias_ J__ _-Location of

CPW contact

pads

module

Figure 5.--Schematic of the SLIC module with the antenna overlay.

4

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1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

June 1996 Technical Memorandum

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

Finite Width Coplanar Waveguide Patch Antenna With Vertical Fed

Through Interconnect

6. AUTHOR(S)

Rainee N. Simons, Richard Q. Lee, Kurt A. Shalkhauser, Jonathan Owens, James

Demarco, Joan Leen, and Dana Sturzebecher

7. PERFORMINGORGANIZATIONNAME(S)AND ADDRESS(ES)

National Aeronautics and Space Administration

Lewis Research Center

Cleveland, Ohio 44135-3191

9. SPONSORING/MONITORINGAGENCYNAME(S)AND ADDRESS(ES)

National Aeronautics and Space Administration

Washington, D.C. 20546-0001

WU- 506--44-2C

8. PERFORMING ORGANIZATION

REPORT NUMBER

E-10066-1

10. SPONSORING/MONITORING

AGENCY REPORT NUMBER

NASA TM-107136

11. SUPPLEMENTARY NOTES

Prepared for the 1996 IEEE AP-S International Symposium and URSI Radio Science Meeting cosponsored by IEEE, APS, and U.R.S.I., Baltimore, Maryland, July 16-21, 1996. Rainee N. Simons, NYMA Inc., 2001 Aerospace Parkway,

Brook Park, Ohio 44142 (work funded by NASA Contract NAS3-27186); Richard Q. Lee and Kurt A. Shalkhauser,

NASA Lewis Research Center; Jonathan Owens, James Demarco, Joan Leen, and Dana Sturzebecher, PSD, Army

Research Laboratory, AMSRL-PS-E, Fort Monmouth, New Jersey 07703. Responsible person, Richard Q. Lee, organization code 5600, (216) 433-3489.

12a. DISTRIBUTION/AVAILABILITY STATEMENT

Unclassified - Unlimited

Subject Category 33

This publication is available from the NASA Center for AeroSpace Information, (301) 621-0390.

12b. DISTRIBUTION CODE

13. ABSTRACT (Maximum 200 words)

The paper presents the design, fabrication and characterization of a finite width coplanar waveguide (FCPW) patch

antenna and a FCPW-to-FCPW vertical interconnect. The experimental results demonstrate the antenna and interconnect

performance. A scheme to integrate an eight element FCPW patch array with MMIC phase shifters and amplifiers using

vertical interconnects is described. The antenna module has potential applications in an advanced satellite to ground

transmit phased array at K-Band.

14. SUBJECT TERMS

Microwave transmission; Microwave antennas; Electronic packaging

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OF REPORT

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Unclassified

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Unclassified

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07

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