A Frequency scanning microstrip antenna using transmission type oscillator is implemented for height finding radar application. The oscillator consists of a second stage amplifier, a frequency scanning microstrip antenna located in feedback path of amplifier, and a phase shifter replaced by physical line. The scan angle of the fabricated scanning antenna is 43.3˚ throughout the range of 7.7 GHz to 8.3 GHz which is the variation of ±3.75% of the center frequency 8.0 GHz. The oscillation frequency is determined by varying line length in the oscillation loop, and the radiation pattern is achieved from the frequency scanning antenna on the feedback path. The frequency variation from 8.065 GHz to 8.205 GHz is obtained. At the same time 12.9˚ scan range is obtained corresponding to those frequency variation. Enhancement of scan range over frequency variation is achieved.
