Compact Millimeter-Wave Filtenna Fed by SIW with BC-CSRRs for Optimal Suppression

The paper proposed a wideband and compact millimeter-wave filtering antenna, referred to as filtenna. The filtenna is fed by a Substrate Integrated Waveguide (SIW) feeding board with optimized cutoff characteristic. Two Broadside Coupled Complementary Split-Ring Resonators (BC-CSRRs) are integrated in the feeding board for optimal stopband suppression. Additionally, the filtenna features tailored radiation structures that enhance its compactness. The proposed filtenna is fabricated and measured. It operates effectively within a 24-32 GHz frequency range, which covers the operating band of n257 and n258 in 5G New Radio (NR). A measured 24.1 dB out-of-band suppression level, with a skirt selectivity of 20 dB/GHz, demonstrates that the filtenna can effectively meet the close proximity of the passband frequency and the local oscillator frequency in the n258 operating band.