A multi-step Ka/Ka dichroic plate (Frequency Selective Surface (FSS)) is designed, manufactured and tested for use in NASA's Deep Space Network (DSN) 34m Beam Waveguide (BWG) antennas. The proposed design allows ease of manufacturing and ability to handle the increased transmit power (reflected off the FSS) of the DSN BWG antennas from 20kW to 100 kW. The dichroic is designed using HFSS and results agree well with measured data considering the manufacturing tolerances that could be achieved on the dichroic.

A technique for a real-time beam aberration correction scheme for deep space uplink and downlink communications is presented. This technique provides a closed-form relationship between the beam aberration angles and the corresponding feed displacement for a reflector antenna with a beam waveguide (BWG) or multiple reflector system. This algorithm will enable one to accurately predict the movement of the feed in real time for a known beam deviation while the antenna is tracking a spacecraft. It is also useful to determine the feed offset position needed to correct for the beam deviation due to an imperfect antenna mechanical structure, and subreflector and mirror misalignments for a complex multiple reflector system.

This article presents the results of tests performed to verify predicted sources of receive antenna gain-to-system noise temperature ratio (G=T ) improvements for the DSS-13 beam-waveguide antenna. The sources that gave the most improvement were (1) covering holography adjustment holes with aluminum-tape circular disks, (2) covering all panel gaps on the main-re∞ector surface with aluminum tape, and (3) installing a liquid-nitrogen load to capture stray signals that normally would be absorbed by an ambient environment. The total measured improvement for all sources of improvement tested was 1.2 K at 8.420 GHz and 2.9 K at 32 GHz. The improvement was larger at 32 GHz because a liquid-nitrogen load test was not performed at 8.420 GHz. I. Introduction The Deep Space Network (DSN) consists of an array of large antennas located worldwide for deep-space communication. Improving the G=T of these antennas and their associated receive subsystems translates into increasing the ground received-signal-to-noise ratios. The symbol G refers to the receive antenna gain and T refers to the system noise temperature. The primary objectives of the G=T improvement task are to (1) identify sources where G=T improvements can be made and (2) verify the predicted values through analysis or experimental work. For convenience, in this article the terms system temperature and operating system temperature, Top, will be used interchangeably to mean system-noise temperature, and the terms S-, X- and Ka-band will be used to refer to center frequencies of 2.295, 8.420, and 32 GHz, respectively. Although the goal is to simultaneously improve bothG andT , the experimental work was restricted to testing only improvements of system temperature. Any receive-system gain changes caused by a change in test conflguration are assumed to be negligibly small or to be predictable through theoretical calculations.

This article discusses the development of a net designed to keeps birds out of the 34-m beam-waveguide antenna opening on the dish surface. Test results on a prototype net showed that the net did not deteriorate when 20 kW at 7.165 GHz were transmitted through it. When dry, the worst-case net contribution to the system-noise temperature was measured to be 0.04 K and 0.18 K at 8.425 GHz and 32 GHz, respectively. When wet, the worst-case net contributions were 0.4 K at 8.425 GHz an d3Ka t 32GHz.

This article presents the results of tests performed to verify predicted sources of receive antenna gain-to-system noise temperature ratio (G=T ) improvements for the DSS-13 beam-waveguide antenna. The sources that gave the most improvement were (1) covering holography adjustment holes with aluminum-tape circular disks, (2) covering all panel gaps on the main-re∞ector surface with aluminum tape, and (3) installing a liquid-nitrogen load to capture stray signals that normally would be absorbed by an ambient environment. The total measured improvement for all sources of improvement tested was 1.2 K at 8.420 GHz and 2.9 K at 32 GHz. The improvement was larger at 32 GHz because a liquid-nitrogen load test was not performed at 8.420 GHz. I. Introduction The Deep Space Network (DSN) consists of an array of large antennas located worldwide for deep-space communication. Improving the G=T of these antennas and their associated receive subsystems translates into increasing the ground received-signal-to-noise ratios. The symbol G refers to the receive antenna gain and T refers to the system noise temperature. The primary objectives of the G=T improvement task are to (1) identify sources where G=T improvements can be made and (2) verify the predicted values through analysis or experimental work. For convenience, in this article the terms system temperature and operating system temperature, Top, will be used interchangeably to mean system-noise temperature, and the terms S-, X- and Ka-band will be used to refer to center frequencies of 2.295, 8.420, and 32 GHz, respectively. Although the goal is to simultaneously improve bothG andT , the experimental work was restricted to testing only improvements of system temperature. Any receive-system gain changes caused by a change in test conflguration are assumed to be negligibly small or to be predictable through theoretical calculations.

The 1.7- to 2.6-GHz (S-Band) transmitter fllter, installed in the beam-waveguide (BWG) antennas, originally was designed for the 34-m high-e‐ciency antennas (HEFs). This fllter operated at a very high physical temperature. In the BWG antennas, this fllter is accessible to the maintenance personnel while the antenna is operational. Therefore, it is considered a safety risk. To reduce the risk, it was decided to design a new fllter with lower insertion loss and better cooling that would lower the physical temperature. The new fllter was specifled at JPL but designed and fabricated at Gamma ‘F’ Corporation. The design replaced copper for aluminum to reduce ohmic loss and added copper cooling flns to help radiate the heat away. This fllter will be installed in Deep Space Station 54 (DSS 54) near Madrid, Spain. In this article, the physical temperatures of the new fllter are presented and compared with the old fllter at various transmitting power levels. The frequency response of the fllter also is provided for future reference.

The Gaussian beam technique has become increasingly popular for a multiple reflector design. This paper demonstrates a new design approach by iterating Gaussian beam and reflector parameters simultaneously at various frequencies to achieve a wideband multiple reflector system. The result can be further improved by comparing it with physical optics results and repeating the iteration.

At the NASA Deep Space Network (DSN) Goldstone Complex, located in the Mojave Desert in California, a 34-meter-diameter beam-waveguide (BWG) antenna, DSS-13, was constructed, and has become an integral part of an advanced systems program and a test bed for technologies being developed to introduce Ka-band (32 GHz) frequencies into the DSN. The antenna efficiency at 32 GHz was found to depend significantly on the elevation angle, i.e., it decreased from 45% to 35% as the elevation angle changed from 45 degrees to 20 degrees. This elevation angle dependence is due to the deformation of the main reflector caused by the resulting change in gravitational force applied to the antenna structure. A method for compensating the gravity-induced structural deformations in a large ground-based beam-waveguide antenna is presented. A deformable flat plate (DFP) is installed at the M6 mirror location in the beam-waveguide optics.

The Ultracone feed system will be implemented on DSS 43 to support the S-band (2.3 GHz) Galileo contingency mission. The feed system will be installed in the host country's cone, which is normally used for radio astronomy, VLBI, and holography. The design must retain existing radio-astronomy capabilities, which could be impaired by shadowing from the large S-band feed horn. Computer calculations were completed to estimate system performance and shadowing effects for various configurations of the host country's cone feed systems. Also, the DSS-43 system performance using higher gain S-band horns was analyzed. A new S-band horn design with improved return loss and cross-polarization characteristics is presented.

The Ultracone feed system will be implemented on DSS 43 to support the S-band (2.3 GHz) Galileo contingency mission. The feed system will be installed in the host country's cone, which is normally used for radio astronomy, VLBI, and holography. The design must retain existing radio-astronomy capabilities, which could be impaired by shadowing from the large S-band feed horn. Computer calcu- lations were completed to estimate system performance and shadowing efiects for various conflgurations of the host country's cone feed systems. Also, the DSS-43 sys- tem performance using higher gain S-band horns was analyzed. A new S-band horn design with improved return loss and cross-polarization characteristics is presented.

This paper presents a new and simple approach for the Ka-band vernier pointing of a 34 m beam-waveguide (BWG) antenna (also applicable to a 70 m antenna). In this study, rotation of a BWG flat mirror, located at the elevation axis, is used to scan the beam instead of using the very large tipping structure of the antenna. The rotation of a BWG flat minor at another location is also investigated. The advantages of scanning the drastically smaller mirror with a less precise mechanism will be discussed. RF performance predictions will be presented.<>

The X-/Ka-band (8.4 GHz/32.0 GHz) dichroic plate installed as DSS 13 contributes an estimated 3 K to the system noise temperature at 32.0 GHz. Approximately 1 percent of the Ka-band incident field is reflected by the plate into the 300-K environment of the DSS-13 pedestal room. A low-cost, easily implemented method of reducing the noise temperature is presented. Using a curved reflector, the reflected field can be re-focused into an 80-K cold load, reducing the noise temperature contribution of the dichroic plate by about 2 K.