Wideband microstrip antenna operating in TM01 mode and its array with compact feed network

This letter presents a broadband linearly polarized (LP) microstrip antenna operating in TM01 mode and its 2 x 2 array with a compact network. Different from the TM10 mode, the TM01 mode can be used to design arrays without a bending feed network. The impedance bandwidth (IBW) of the proposed antenna is 9.6% (2.19 GHz-2.41 GHz). Subsequently, the characteristic of this antenna operating in TM01 mode is employed to design a 2 x 2 planar array. The measured results show that the array has an IBW of 9.5%, a maximum gain of 11.4 dBi with low cross-polarization.