Microstrip Antenna Size Reduction Using Feeding Structure

This paper presents a compact size microstrip patch antenna for L-band application. Overall /spl sim/75% size reduction has been achieved as compare to conventional microstrip antenna for same frequency band. We have designed dual fed microstrip patch antenna to obtain wide frequency band. Branch line coupler is used for 90/spl deg/ phase shift between two vertical feed and equal power coupling. Further, delay line has been designed between branch line coupler and microstrip patch for resonant frequency reduction. We can change the resonant frequency of a microstrip patch by changing the physical parameters of the delay line.