Novel-integrated patch antennas with multi-band characteristics

In this study, two integrated multi-band microstrip patch antennas have been proposed for the next-generation wireless systems. The first design consists of a right isosceles triangular patch integrated with a pair of monopoles. The patch resonates at 3.5 GHz (WiMAX, worldwide interoperability for microwave access) and the monopoles at 2.45 GHz (WLAN, wireless local area network) and 1.96 GHz (PCS frequency), respectively. Furthermore, to improve the gain profile and to achieve directive radiation characteristics towards zenith, a reflector ground plane has been placed below the patch. The detailed analysis of the pattern synthesis technique has been explained. Similarly, the second proposed design consists of a semi-circular patch resonating at 3.5 GHz integrated with a slot and a monopole. The slot and monopole resonate at 5.5 GHz (WiMAX) and 2.45 GHz, respectively. Both the designs are realised on a 1.58 mm-thick FR4 substrate (dielectric constant 4.4) and have a return loss better than 10 dB with desired radiation characteristics at the specified resonant frequencies. Prototypes of the proposed designs have been fabricated and their radiation characteristics have been measured. A close agreement has been found between simulation and measurements.