Dual-Band Decoupling Method for Millimeter-Wave High-Isolation Wide-Angle Scanning Phased Array Antenna

A novel dual-band decoupling method is proposed and applied to millimeter-wave phased array for wide-angle scanning. By introducing comb-shaped branch, “I”-shaped branch and grounded vias simultaneously, two kinds of extra decoupling paths are generated to cancel the inherent couplings at two frequencies, respectively, thus achieving dual-band decoupling. To verify the decoupling structure, a broadband magneto-electric (ME) dipole antenna is designed, ranging from 24.13 to 45.17 GHz (60.7
^%
), which can cover the main 5G operating frequency bands of 24.25-29.5 GHz and 37-43.5 GHz. Then, the two decoupling structures are loaded on the lx4 antenna array. The isolations between all the elements in both the two operating bands are greater than 20 dB, and compared with the array without decoupling structures, the isolations are improved by at least 5 dB. Benefited from the dual-band decoupling, the scanning range can cover from −64° to 63° in the low frequency band nearby 28GHz, with a gain fluctuation of 2.4 dB, meanwhile the array at high frequency band nearby 40GHz can scan up to
$\pm 48^{\mathrm{o}}$
, with a gain fluctuation less than 3 dB. Besides, the proposed method can be expectedly applied in larger scale array.