Planar Broadband Higher-Order Mode Millimeter-Wave Microstrip patch Antenna Array with Low Sidelobe Level

Abstract

AbstractIn this letter, a planar broadband higher-order mode millimeter wave (MMW) microstrip patch antenna array with low sidelobe level (SLL) is presented. For the antenna element, antiphase-TM30 mode is excited by unequally etching the radiating patch with two transverse slots. Meanwhile an SIW-based pin-loaded slot coupling feeding structure is introduced to achieve merits of broadband, low cross polarization and low backward radiation. Then a one-eight power divider with in-phase unequally tapered amplitude distribution is adopted to excite an eight-element array with SLL. The GCPW-SIW transition structure is also selected to achieve broadband impedance matching. Finally, both element and array antenna are optimized and fabricated for verification. For the antenna array, the measured -10 dB impedance bandwidth is from 25.1 to 31.3 GHz (22%) with a maximum gain of 14.6 dBi at 29.5 GHz and a 3dB gain bandwidth of 27.9%. And the measured SLL at 26, 28 and 30 GHz are all less than 20 dB. Index TermsMillimeter-wave (MMW), broadband, higher-order mode, low sidelobe level (SLL).