Proximity Coupled Square Patch Array Antenna for L-Band Radar with Sequential Phase Feeding Network

The use of array antenna which has a sequential phase characteristic is sometimes required for a specific radar application. This paper deals with the design and characterization of proximity coupled square patch array antenna with sequential phase feeding network are presented for L-band radar. The proposed array antenna designed to work at the L-band frequency of 1275 MHz is constructed by 1×4 slotted and truncated corner square patches. The use of proximity coupled feed as well as corner truncation is to yield wide bandwidth response, while the slot over square patch is applied to attain circularly polarized waves. The array antenna is deployed on two layers of 1.6 mm thick flame retardant (FR) 4 epoxy dielectric substrate with the width of 95 mm and the length of 312 mm. The characterization results show that the -10 dB fractional impedance bandwidth is 5.5% in the frequency range of 1212 MHz to 1280 MHz with the 3dB axial-ratio bandwidth of 54 MHz from the frequency of 1222 MHz to 1276 MHz.