Compact balanced filter with high common mode suppression using hybrid microstrip and slotline spoof surface plasmon polaritons

Hybrid folded microstrip and slotline (HFMS) spoof surface plasmon polaritons (SSPPs) are developed to design a balanced bandpass filter (BPF). The proposed HFMS SSPPs can lower the upper cut-off frequency for size reduction of nearly 65%. Microstrip-to-slotline transition structure is adopted feeding structure. Under differential mode (DM) operation, band-pass response formed by high-pass microstrip-to-slotline low-pass SSPP common (CM) high CM suppression achieved due intrinsic rejection ability Finally, BPF with compact fabricated, measured.