A Tri-Band Low-Profile High-Gain Planar Antenna Using Fabry-Perot Cavity

A tri-band antenna with high gain and low profile is

proposed. This antenna is based on the concept of Fabry-Perot

cavity antenna (FPCA) and three resonances are obtained by

employing two frequency selective surface (FSS) layers. Two FSS

layers lead to two resonant frequencies by making each FSS layer

satisfy the resonant condition of Fabry-Perot cavity. The third

resonant frequency is obtained by exploiting the combined effects

of the two FSS layers together. The operating principle of this

proposed antenna is explained and the achievable frequency

range is investigated. It is shown that the proposed method

enables all three resonant frequencies to be independently tuned

within certain frequency range. Because of the 0o reflection phase

of the combined-FSSs, the present antenna has a low profile. To

verify the design concept, one C/X/Ku-band FPCA is designed,

fabricated and tested. Experimental results agree well with the

simulated results. High gain with good impedance matching in

three bands is obtained, which reaches a peak gain of 13.4 dBi at

5.2 GHz, 18.9 dBi at 9.7 GHz and 20 dBi at 14.6 GHz. The overall

height of the proposed antenna is approximately 0.36 wavelength

at its lowest operating frequency.