Harmonic-Suppressed Dual-Resonance Decoupling Network With Near-Zero Insertion Loss for Patch Antenna Arrays

To suppress the coupling among patch antenna arrays and reduce out-of-band spurious, a feeding-decoupling network with harmonic suppression is proposed. The decoupling method achieved by generating two paths between feeding of an radiating adjacent antenna, through slotline-based lowpass filter miniaturized coupled line coupler. Despite no operation non-adjacent elements, them also reduced. are realized sharing same structures, making physical layout compact. For demonstration purposes, design $1\times $ 8 array working at 4.9 GHz, integrated proposed structure developed. results indicate that within impedance bandwidth from 4.8 to 5.1 both elements suppressed less than −25 dB. Besides, spurious up 12 GHz well suppressed. in-band total efficiency decoupled higher 80%. There nearly insertion loss resulting only notation="LaTeX">$50 \Omega transmission lines utilized very few discontinuities, as expected.