A Low Profile Pattern Reconfigurable Antenna With Enhanced Bandwidth And Gain

A new compact pattern reconfigurable antenna with enhanced bandwidth is presented. The antenna consists of a circular radiation patch, a circular feeding patch and five shorting posts in which four shoring posts are connected to the ground via PIN diodes. By switching PIN diodes on or off, the proposed antenna can operate in either monopolar patch or normal patch mode in similar frequency ranges. Thus, its radiation pattern can be switched between conical and boresight pattern electrically. The bandwidth is improved by a capacitive coupling in conical mode and by employing a shorting post in the normal patch mode. The measured overlapping impedance bandwidth for -10 dB criteria of the two modes covers 3.34 -3.62 GHz, which is 8%. Placing the PIN diodes on the ground instead of patch layer allows more freedom to optimize the realized gain for normal patch and monopolar patch mode respectively. The antenna can be used as a pattern diversity antenna for modern mobile communications.