A 34-m beam-waveguide (BWG) antenna has been built a Deep Space Station 13 (DDS 13) in the Goldstone Deep Space Communications Complex. This antenna is designed to be efficient at X-, Ku-, and Ka-bands, and it is the first NASA tracking antenna to use a BWG design. The design of a Ku-band test package for the new BWG antenna at 11.7-12.2 GHz is presented. Results of linear polarization measurements with the test package on the ground are also presented. This report is the fifth in a series of articles concerned with test package design and performance

Franco, M. M.

Otoshi, T. Y.

Stewart, S. R.

English

NASA Technical Reports Server

TDA Progress Report 42-107
f.X
November 15, 1991
N92-14244
A Portable Ku-Band Front-End Test Package for Beam-
Waveguide Antenna Performance Evaluation
T. Y. Otoshi, S. R. Stewart, and M. M. Franco
Ground Antennas and Facilities Engineering Section
This article presents the design of a Ku-band test package for the new beam-
waveguide (BSVG) antenna at 11.7-12.2 GHz. Results of linear polarization mea-
surements with the test package on the ground are also presented. This report is
the fifth in a series of articles concerned with test-package design and performance.
I. Introduction
A new 34-m beam-waveguide (BWG) antenna has been
built at Deep Space Station 13 (DSS 13) in the Goldstone
Deep Space Communications Complex near Barstow, Cal-
ifornia. This antenna is designed to be efficient at X-, Ku-,
and Ks-bands, and it is the first NASA tracking antenna
to use a BWG design. The antenna's focal points for the
center-pass mode are shown in Fig. 1.
The unique methodology used to test the new BWG
antenna included making measurements at the Cassegrain
focal point and then at the final focal point in the pedestal
room. Measurements made at the Cassegrain focal point
F1 give information concerning panel settings, subreflec-
tor defocus, and far-field antenna patterns. Measurements
made at the pedestal room focal point F3 provide am-
plitude and phase information on the entire BWG sys-
tem, which includes the main reflector, subreflector, and
six BWG mirrors. Degradations caused by the BWG mir-
ror systems are determined by comparing tile measured
parameters at the two focal points. Previous articles [1-
4] describe the successful employment of X- and Ks-band
test packages for the new DSS 13 BWG antenna at 8.45
and 32 Gttz.
This is the fifth article in a series of reports on the de-
sign and performance of X-, Ks-, and Ku-band test pack-
ages that were developed specifically for testing the BWG
antenna. The Ku-band test package is used primarily for
making holographic measurements [5]. In this article, only
a description of the Ku-band test package and results from
a linear polarization test will be given. In another report,
it was shown that the Ku-band test package was used
successfully at the BWG antenna Cassegrain focal point
F1 to obtain holographic panel-setting information) The
Ku-band test package will be employed in the near fu-
ture for making holographic measurements at F3 and also
for making BWG frequency-stability measurements, as de-
scribed in a companion article [6].
I B. L. Scidel and D. J. I:(odlblatt, Chapter 4, DSS. 13 Beam-
IVaveguide Antenna Project, Phase 1 Final Report, JPb D-8,151
(internal document), Jet Propulsion Labo,'atory, Pasadena, Cali-
fornla, lkIay 15, 1991.
73
https://ntrs.nasa.gov/search.jsp?R=19920005026 2020-03-17T14:38:26+00:00Z
II. Ku-Band Test-Package Design
Figure 2 shows the system block diagram of the
Ku-band test package. Depicted are such Cassegrain
front-end microwave components as the horn, cosine ta-
per, circular waveguide rotary joint, the circular wave-
guide to waveguide-rectangular (WR) 75 transition, and
the low-noise amplifier (LNA). The microwave system is
designed to operate over a Ku-band frequency range of
11.7-12:2 GHz. For holographic measurements, an Eikon-
tech Holographic Receiver system was used to downcon-
vert the Ku-band frequency to an intermediate frequency
(IF) of approximately 482 MHz.
The 22-dBi horn assembly has an aperture diameter of
5.004 in. and tapers linearly over a length of 18.414 in.
to a diameter of 0.968 in. A 4-in.-long cosine taper pro-
vides a gradual transition from the horn output diameter
III. Test Results
Figure 5 is a photograph of the Ku-band test package
undergoing linear polarization tests at JPL. A block di-
agram of the test setup appears in Fig. 6. The transmit
horn was pyramidal (Scientific-Atlanta model 12-7.0), with
aperture dimensions of 5.04 x 3.73 in. and WR 112 at its
input. The separation distance of 44.2 in. corresponded to
1.72 D_/A, where A is the free-space wavelength for the
test frequency of 11.95 GHz, and D corresponds to the
5.04-in. dimension of the pyramidal horn. Linear polar-
ization tests were performed by rotating the lower half of
the test-package circular rotary joint and measuring re-
ceived signal levels with the equipment shown in Fig. 6.
The results of the polarization tests are given in Fig. 7.
Good agreement was obtained between theoretical and ex-
perimental data. The measured depths of the nulls were
of 0.968 in. to the circular rotary joint diameter of 0.879 in. _-47 dB down from the peak when the two horns were
The Ku-band circular waveguide rotary joint is a scale cross-polarized with respect to each other. The test re-
model of the DSN version used in the X-band test pack-
age [1] and other Cassegrain cone assemblies. To enable
linear polarization to be varied to the desired rotation an-
gle, the LNA is supported by a pair of orthogonal brackets
with an axle-hole design that permits the amplifier (and
follow-up coaxial cable) to be manually rotated 360 deg. A
clamp is used to prevent further rotation of the assembly
once the optimum linear polarization-output orientation is
found for the incoming signM.
Testing the antenna at F1 and F3 required the test
package to be convertible from 29- to 22-dBi horn con-
figurations. The conversion is accomplished by using horn
extensions of the same linear taper going from an aperture
diameter of ,,_13.46 to 5.004 in., over a length of 38.58 in.
Figure 3 shows the Ku-band test package in the 29-dBi
horn configuration installed at the Cassegrain focal point
F1. Figure 4 shows the test package in the 22-dBi horn
configuration ready for installation on the mounting table
at focal point F3. The height of the 29-dBi horn config-
uration, as measured from the horn aperture to the base
of the frame assembly, is about ll ft, while the height of
the 22-dBi horn test-package configuration is about 39 in.
shorter.
sults verified that the Ku-band test-package system would
receive linearly polarized signals at desired rotation angles
and reject cross-polarized signals.
The Y-factor noise-temperature measurements made
with aperture-ambient_ and liquid-nitrogen loads showed
that the Ku-band operating noise temperature was 172 K,
as defined at the Ku-band horn aperture. Most of this op-
erating noise temperature was due to the 160 K LNA in
the system (see Fig. 2).
IV. Concluding Remarks
The Ku-band test package was tested in an on-the-
ground configuration and was found to perform according
to the design goals. Other reports showed that the test
package was stable and performed well when used at the
BWG Cassegrain focal point F1 for holographic measure-
ments at 46.5- , 37.0- , and 12.7-deg. elevation angles. 2
2 Ibid.
74
Acknowledgment
The authors gratefully acknowledge H. Reilly who provided the Ku-band rotary
joint for the test package.
References
[1] T. Y. Otoshi, S. R. Stewart, and M. M. Franco, "A Portable X-Band Front-End
Test Package for Beam-Waveguide Antenna Performance Evaluation--Part I:
Design and Ground Tests," TDA Progress Report 42-103, vol. July-September
1990, Jet Propulsion Laboratory, Pasadena, California, pp. 135-150, Novem-
ber 15, 1990.
[2] T. Y. Otoshi, S. R. Stewart, and M. M. Ffanco, "A Portable X-Band Front-End
Test Package for Beam-Waveguide Antenna Performance Evaluation--Part II:
Tests on the Antenna," TDA Progress Report 45-105, vol. January-March 1991,
Jet Propulsion Laboratory, Pasadena, California, pp. 54-68, May 15, 1991.
[3] T. Y. Otoshi, S. R. Stewart, and M. M. Franco, "A Portable Ka-Band Front-End
Test Package for Beam-Waveguide Antenna Performance Evaluation--Part I:
Design and Ground Tests," TDA Progress Report 42-106, vol. April-June 1991,
Jet Propulsion Laboratory, Pasadena, California, pp. 249-265, August 15, 1991.
[4] T.Y. Otoshi, S. R. Stewart, and M. M. Franco, "A Portable Ka-Band Front-End
Test Package for Beam-Waveguide Antenna Performance Evaluation--Part II:
Tests on the Antenna," TDA Progress Report 42-I06, vol. April-June 1991, Jet
Propulsion Laboratory, Pasadena, California, pp. 266-282, August 15, 1991.
[5] D. J. Rochblatt and Y. Rahmat-Sammi, "Effects of Measurement Errors on Mi-
crowave Antenna Holography," IEEE Transaclions on Antennas and Propaga-
tion, vol. 39, no. 7, pp. 933-942, July 1991.
[6] T. Y. Otoshi, "A Proposed Far-field Method for Frequency Stability Mea-
surements on the DSS 13 Beam-Waveguide Antenna," TDA Progress Report
45-107, vol. July-September 1991, Jet Propulsion Laboratory, Pasadena, Cali-
fornia, pp. 81-87, November 15, 1991.
75
SHAPED-SURFACE
SUBREFLEq
SHAPED-
SURFACE
REFLECTOR
F1
_SHROUD FOR ___ _ BEAM
A BYPASS WAVEGUIDE
,VEGUIDE
SYSTEM
TRACK
MICROWAVE
TEST
ROOM
Z---"E
REAR VIEW
Fig. 1. The BWG antenna in the center-pass mode, showing focal
points F1, F2, and F3 for testing with the portable test package.
76
-92 in.
L___
t / _ 29-dBi HORN EXTENSION
._ (NOT TO SCALE)
T/-- 22-dBi HORN
__._. _ APERTURE
TEST-PACKAGE _ / 22-dBi H_ORN
BASIC FRAME 1 I (NOT TO SCALE)
ENCLOSURE _ COSINE TAPER
ROTATABLE I['_] CIRCULAR ROTARY JOINT
LINEAR _ i_
POLARIZATION LI Iwc-wR TRANSITION
ROOM
TEMPERATURE
LOW-NOISE
AMPLIFIER
53.4-dB GAIN,
160 K NOISE
TEMPERATURE,
11.7-12.2 GHz
_t
r ]
HOLOGRAPHY I
I DOWNCONVERTER
I (CONTRACTOR PROPERTY) I
[ J
IF = 482 MHzI l f REFERENCE
__ __ __ ._L=. 101 MRz
/
" Y- " /
JTO PEDESTAL-ROOMHOLOGRAPHYEQUIPMENT
34 in.
Fig. 2. A block diagram of the Ku-band test-package system.
77
Fig. 3. The Ku-band test package mounted at F1 in the
29-dBi horn configuration.
Fig. 4. The Ku-band test package assembly In the 22-dBI horn
configuration prior to Installation on the mounting table at F3.
78
ORIGINAL PAGE
BLACK AND WHITE P_'_hTOGRAPI..t
;\
Fig. 5. The test setup for linear polarization tests on the Ku-band lest package st JPL.
ORI_rF,IAE PAG£
BLACK AND WHITE PHOTOGRAPH
79
HP8350B
SWEEP OSCILLATOR
HP436A
POWER METER
WC CIRCULAR
WAVEGU1DE
WR RECTANGULAR
WAVEGUIDE
___ HP8495B J
ATTENUATOR J
30-dB PAD _.-
15-ft FLEXCO CABLE
SCIENTIFIC _ TRANSITION
ATLANTA
MODEL 12-7.0 O
SERIAL NO. 71
GAINSTANDARDHoRN ._ _ TRANSITION
JPL 9499180
AND 9499181
22-dBi HORN
JPL 9486280
COSINE TAPEF
WC ROTARY
JOINT
JPL 9486279
WC TO WR 75
FOUR-STEP
TRANSITION
11.950 GHz
BANDWIDTH = 50 MHz
3"
44.2 in.
-I
LNR 406012621-1 J
SERIAL NO. 342 1LOW-NOISEAMPLIFIER
Fig. 6. A block diagram of the linear polarization test setup at 11.950 GHz.
m
1D
_-20
a.
LU
>
,_ -30
LU
n"
-I0!
-4O
I
60
._f
05-02-90 MEASUREMENT
Ku-BAND TEST PACKAGE
FREQUENCY = 11.950 GHz
22-dBi HORN CONFIGURATIOI_
JPL BUILDING 238 ROOF
-50 _ 1 , ] , I ,.. t ,
0 120 180 240 300 360
POLARIZATION ANGLE e, deg
Fig. 7. Theoretical and experimental polarization loss versus
polarization angle.
8O


A portable Ku-band front-end test package for beam-waveguide antenna performance evaluation

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