Broadband Microstrip Beam Deflector Based on Dual-Resonance Conformal Loops Array

A new single-layer microstrip dual-resonance conformal loop (DRCL) element is proposed to design a printed beam deflector array for broadband application. By utilizing variable parameters of the DRCL element, a nearly progressive phase-shift ranging more than 550 ° is achieved for deflecting wave within a wide band. It is important that a small DRCL element can be flexibly used to generate a 360 ° phase shift, which decreases the cell period between the neighboring elements. The DRCL is less sensitive to the variation of incidence angles for both TE and TM polarizations. An X-band plane wave beam deflector array is designed, fabricated and measured. The results show a significant improvement in gain-bandwidth performance of the deflector array using the new structure element. The 1 dB gain-bandwidth of 20% can be achieved. The measured results agree well with the simulation results.