Frequency Reconfigurable Antenna Considering Radiation Beam Width

A frequency reconfigurable microstrip antenna is proposed. A circular patch and a C-shaped ring are used for different frequency bands and the two parts are connected by the PIN diode. The two parts can be one resonator when the PIN diode is shorted, otherwise to make the two parts independent. Because the main resonators are different for the different bands, the beam widths can be tuned to be similar for both bands. Simulated results show that the proposed antenna can cover frequency bands of 4.64–4.7GHz and 7.77–7.9GHz with reflection coefficient below −10 dB. The 3dB beam widths are between ± 40° to ±47°.