A novel low profile box-shaped antenna for a repeater system

This paper presents a novel microstrip slot antenna based on box-shaped structure suited for a repeater system in the mobile communication cellular band (890MHz-960MHz). With the aid of folded-slot technique, the overall antenna size is only about 0.29λ × 0.29λ × 0.037λ (λ is the wavelength corresponding to the lowest edge of the operating band 860MHz). A 13.6% simulated impedance bandwidth, ranging from 865MHz to 990MHz, is obtained within 2:1 VSWR (Voltage Standing Wave Ratio). Furthermore, the prototype of the antenna is constructed and tested, and a 15% impedance bandwidth is observed. Experimental study is carried out by varying the height of the box. Simulated and measured results all show that this antenna exhibits wideband and low profile characteristics.