A Miniaturized Dual-Band Dual-Beam Filtering Patch Antenna With Orthogonal Beam Pointing

A miniaturized dual-band dual-beam filtering patch antenna with orthogonal beam pointing is proposed. By using a cross-shaped feedline with two pairs of orthogonal common-mode (CM) currents, TM02 and TM20 modes are excited with suppression of adjacent TM10 and TM12 modes, and radiation null 1 (RN1) is introduced in both polarizations. Due to far-field nulls of orthogonal dual-beam patterns, intrinsic radiation null 1 (RNi1 ) and RNi2 are generated. With miniaturization, by etching periodic short slots, RNi3 related to the high-order harmonic can be used, its frequency can be significantly controlled, and the radiation pattern is reshaped to effectively improve the rejection at RNi3 in x -polarization. To ensure high selectivity at each sideband while remaining compact, nested two quasi-circular loops (QCLs) and a cross-shaped metal strip (CSMS) are employed to create RN2-RN4 in both polarizations. Thus, a total of eleven RNs are yielded, aching high selectivity and deep stopband rejection. With a small size of 0.40 lambda(0) x 0.44 lambda(0)x0.028 lambda(0), a prototype is fabricated and tested. Measured results show that dual beams in 5.3-5.53 GHz point toward the x -axis direction, while dual beams in 6.34-6.66 GHz point toward the y -axis direction, satisfying the requirements of point-to-multipoint scenarios providing different wireless services in orthogonal orientations.