Chun-Kun Wu

Novel compact circularly polarized square microstrip antenna

A novel compact circular-polarization (CP) operation of the square microstrip antenna with four slits and a pair of truncated corners is proposed and investigated. Experimental results show that the proposed compact CP design can have an antenna-size reduction of about 36% as compared to the conventional corner-truncated square microstrip antenna at a given operating frequency. Also, the required size of the truncated corners for CP operation is much greater than that for the conventional CP design using a simple square microstrip patch, providing a relaxed manufacturing tolerance for the proposed compact CP design. Details of the experimental results are presented and discussed.

Square-ring microstrip antenna with a cross strip for compact circular polarization operation

A novel design of square-ring microstrip antenna with a cross strip for achieving compact circular polarization (CP) operation is proposed and experimentally studied. The cross strip can be placed in the centerlines or diagonals of the square-ring patch. Either design can make its excited fundamental mode patch surface current path much longer than that in a conventional square microstrip antenna with same antenna size. By incorporating a small tuning stub for splitting the fundamental mode into two near-degenerate resonant modes with equal amplitudes and 90/spl deg/ phase-difference compact CP operation for the proposed design can he obtained.

Inset microstripline-fed circularly polarized microstrip antennas

Circular polarization (CP) designs of inset microstripline-fed microstrip antennas are proposed. Three designs with a single slit, two pairs of slits, and three pairs of slits are experimentally studied. Good CP performances of the proposed antennas are achieved. For the design with three pairs of slits studied here, the center CP frequency is also seen to be lowered by about 33% compared to the case without slits, which suggests that an antenna size reduction as large as 55% can be obtained if the proposed design is used in place of a conventional CP design at a fixed frequency.