Record Details
A signal-processed antenna system and the simulation of the effects of balanced-mixer frequency conversion
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | A signal-processed antenna system and the simulation of the effects of balanced-mixer frequency conversion |
| Names |
Spencer, Kenneth Edward
(creator) Alexander, Gerald C. (advisor) |
| Date Issued | 1968-05-10 (iso8601) |
| Note | Graduation date: 1968 |
| Abstract | In this paper a signal-processed antenna and receiver system is proposed and analyzed. In addition, a simulation of the balanced-mixer portion of the processing system is made on a hybrid computer to find the bandwidth limitations for the total system. The system utilizes both the amplitude and phase information of a one-dimensional antenna array as compared to only amplitude information for normal antenna systems. The proposed processing system is analyzed by using a simplified model for the balanced-mixer portion of the processor. The analysis is done both for a processor with a CW local oscillator and for one with a pulsed local oscillator. The analysis shows that, in addition to the normal amplitude factors in the processor output signal and in the effective electric field pattern, a phase-dependent amplitude factor is obtained. It is shown that, by a method of phase manipulation, this phase-dependent term is made to depend only on the characteristics of the antenna array, the displacement of a reference antenna from the center of the antenna array and a pattern control shift. The method of phase manipulation uses the processed signal from the reference antenna to adjust the phase of the antenna array signal at the receiver. The pattern control phase shift is used to put a null or maximum in the direction of the pattern maximum for simple amplitude detection. The analysis indicates that the phase manipulated term in the effective pattern can be used to improve the pattern over that for simple amplitude detection. The pattern improvement consists of at most a sidelobe reduction of 5.3 db or beamwidth reduction by a factor of two. The bandwidth limitations of the information signals carried on the receiver input signal for reproduction of the information is found to be similar to other detection systems. In the simulation of the balanced-mixer portion of the processing system, the balanced-mixer transmission lines are considered to be lossless and free of dispersion. Also, the junctions are considered to be lossless and free of energy storage. The simulation results indicate that the simulation on the hybrid computer gives a very representative model for the balanced-mixer operation. From the simulation results, it is shown that the bandwidth for pulsed input signals to hold normal beam-pointing accuracies is in the range of 2-9% of the local oscillator frequency. The useable bandwidth range of the processor for a CW input signal is found to be about 17%. Also, it is found that the simplified, balanced-mixer model should be used only for a representive analysis for a 10% bandwidth. In addition, the simplified model should not be used alone for pulsed input signals when the phase information is important. |
| Genre | Thesis/Dissertation |
| Topic | Antennas (Electronics) |
| Identifier | http://hdl.handle.net/1957/47041 |
