Truncated rhombic microstrip patch array antenna with frequency reconfigurability

A novel design of frequency reconfigurable microstrip array antenna (FRMAA) using aperture coupler feeding technique is presented. In contrast with conventional antennas that can be operated at one frequency in a single antenna, this FRMAA is capable to operate at two different frequencies. In this paper, the ground plane which is located in the middle of the two substrates serves as a very effective shield between the radiating aperture and the feed. By having this type of configuration, unwanted effects such as spurious feed radiation can be reduced and substrate space for antenna elements and feed line can be increased. The integration of PIN diode switch concept with the feed network enables the antenna to operate at two different frequencies, 5.3GHz and 5.8GHz. The variations in the position and design of the patch slot would affect the excitation of the resonant frequencies. The proposed antenna has been designed and optimized using CST Microwave Studio. Two different frequencies have been achieved by using the same patch size and 26% of patch size reduction has been obtained for the lower frequency. The results confirmed that the antenna can be operated at two different frequencies with considerably high gains.