Microstrip-fed slot antennas backed by a very thin cavity

Abstract

Slot antennas with a backing cavity for unidirectional radiation are investigated with the aim of achieving a thin structure capable of reasonably broadband operation. By tuning together the slot length and the cavity cross-section, a very low-profile cavity-backed slot (CBS) is demonstrated. The cavity thickness of this slot antenna is about 10 times smaller than conventional one-quarter wavelength cavities, which would allow constructing this antenna even with standard cost-effective multilayer planar technology. The high gain and fairly wide-band operation are the major advantages of the proposed configuration, which features a bandwidth of about 10% at a center frequency of 1.8 GHz with radiation efficiency in excess of 80%. Measured data are presented and compared with simulation results obtained by both the method of moments (MoM) and the finite integration technique (FIT). © 2006 Wiley Periodicals, Inc.