A Wideband Coplanar L-Probe-Fed Slot-Loaded Rectangular Filtering Microstrip Patch Antenna With High Selectivity

A coplanar L-probe slot-loaded wideband filtering microstrip antenna is proposed in this letter. The filtering properties are realized by the introduction of four slots and a coplanar L-probe. A standard TM20 mode is excited to attain the radiation null at the lower band. Moreover, a standard TM21 mode and the L-probe contribute to the two radiation nulls at the upper band. The slots also excite new resonant modes to enhance the bandwidth of the antenna. The analysis reveals that a traditional TM01 mode and a reshaped TM21 mode are excited and couple with each other to realize a wide bandwidth. The measurements reveal that the proposed antenna has a 10 dB impedance bandwidth of 14% from 2.32 to 2.63 GHz with a peak gain of 9.24 dBi at 2.48 GHz. The gain variation is less than 1 dB within the passband. The advantages of simple structure, coplanar, easy fabrication make the proposed antenna suitable for various wireless communication systems.