Dual-Band Antenna With Pattern/Polarization Diversity For 2.4/5-GHz WLAN Applications

A low-profile dual-band antenna with polarization/pattern diversity is proposed for 2.4/5-GHz wireless local area network (WLAN) applications. The lower-band element is composed of four shorted patches, which are excited in-phase and equal magnitude to generate omnidirectional radiation pattern with vertical polarization. The higher-band element is a differential-fed circular patch encompassed by eight mushroom-type structures to generate a wideband broadside dual-polarized radiation. The internal corners of the lower-band patches are truncated to embed the higher-band element without any overlap, and consequently, achieve a compact size. The final design with overall size of 0.57λ2.4-GHz× 0.57λ2.4-GHz × 0.03λ2.4-GHz yields a 10-dB return-loss bandwidth of 70/1050 MHz and realized gain of 0.39/9.9 dBi at 2.4/5-GHz WLAN bands, respectively. Also, the antenna achieves an isolation of ≥30 dB through both lower- and upper-bands.