Taneaki Chiba

A Phased Array Antenna using Microstrip Patch Antennas

A phased array antenna using microstrip for tne AMES (Aeronautical Maritime Engineering Satellite) airborne antenna. The phased array antenna has tested over a frequency range from 1.54 to 1.65 GHz. Scanning abilities up to +30 degrees have been verified over above the frequency range. The V.S.W.R is less than 2 to 1 over 8.4 percent bandwidth. By using the method suppressing the higher modes, the boresight axial ratio has been reduced to less than 0.8 dB.

Cylindrical Phased Array Antenna for SSR-Mode S System

A cylindrical conformal phased array antenna which is a candidate of SSR(Secondary Surveillance Radar) antenna for next generation is experimentaly constructed and tested. This antenna is consisted of broadband microstrip patch antennas. Band broadening is achieved by honeycomb structure[1] [2] and attains about 6% bandwidth. In order to obtain a good elevation pattern, mutual coupling effect is considered in design and the fine elevation pattern is obtained.

Newly Developed Co-Feed Type SSR Antenna

The new type Secondary Surveillance Radar (SSR) antenna which has use Air Route Surveillance Radar (ARSR) reflector has been developed. The typical SSR uses a relatively small antenna on the top of the radar reflectors. The small vertical dimension of the antenna produces a very wide elevation beamwidth which does not discriminate against interrogation or replies reflected from the ground or sea. This problem can be overcome by utilizing the ARSR reflector for the SSR, that is, the particular dual horn arrangement is used and the appropriate combination of the two outputs of the dual offset feeds can be compensate for the elevation offset angle and coincide the beam noses of the ARSR and the SSR pattern. This particular feed design also provides excellent horizontal SSR pattern which is optimum for monopulse tracking. The SSR antenna is effectively used as a senser of Discrete Address Beacon System (DABS).