Engineering topics
Publications and source records attributed to Cramer, P..
Reflector antenna optimization schemes using array feeds have been used to recover antenna losses resulting from antenna distortions and aberrations and to generate contour coverage patterns.
As a part of the long-range planning of future Mars and lunar missions, a rudimentary study has been made of a 34-m antenna system with differentially pointed multiple beams. The performance loss mechanisms of the differentially pointed multiple-beam systems were identified and quantified. The goal is to determine the feasibility of using the 34-m antenna to support widely separated elements associated with lunar missions.
As a part of the long-range planning of future Mars and lunar missions, a feasibility study was made of a 34-m antenna system with differentially pointed multiple beams. The performance loss mechanisms of the differentially pointed multiple-beam systems were identified and quantified. Techniques that can significantly improve the multiple-beam system performance are identified. The goal is to determine the feasibility of using the 34-m antenna to support widely separated elements associated with lunar missions.
Reflector-antenna calculations using idealised truncated feed patterns can lead to incorrect values of total secondary radiated power. It is demonstrated that this discrepancy is due to the presence of higher-order spherical modes incident on the reflector. When a proper spherical-wave expansion of the incident field is used, in conjunction with the physical-optics technique, to determine the scattered field, the total power of the scattered field will equal the power radiated by the feed.
The attached manipulator system (AMS) is to simulate and demonstrate zero-g shuttle manipulator cargo handling operations. It is not the design or development of the shuttle attached manipulator system (SAMS); however, every effort is being made, to insure that the AMS will be functionally similar to the SAMS.