Multilayer multiresonator circular microstrip antennas for broadband and dual-band operations

Different methods to increase the bandwidth of a microstrip antenna, such as use of an air-gap in-between stacked resonators and the ground plane and planar multiresonators. are combined to achieve broad bandwidth with increased gain. A configuration with two gap-coupled circular microstrip antennas on the top dielectric layer stacked with one coaxial-fed circular patch on the bottom layer and all air-gap in-between two layers and the ground plane yield a bandwidth of 1093 MHz (47%) with a gain of 9.54 dB at the S-band frequency of 2.325 GHz. Also, dual-band response with broadside radiation and improved gain at both frequencies is achieved by suitably changing parameters of this configuration. Parametric studies of this configuration oil dielectric substrate for both broadband and dual-band operation are presented in this paper. The experiments are performed oil broadband and dual-band configurations, which are ill agreement with the theoretical results. (c) 2005 Wiley Periodicals. Inc.