基于人工表面等离激元的小型化高共模抑制平衡式滤波功分器

In this article, a compact ultrawideband balanced filtering power divider (FPD) with controllable cutoff frequencies is proposed based on the spoof surface plasmon polaritons (SSPPs). First, a compact SSPP unit cell is designed using the I-shaped microstrip structure for size miniaturization, and the dispersion characteristics are analyzed. Next, a balanced high-pass power divider (PD) with high common mode (CM) suppression level is designed using the microstrip-to-slotline (MTS) transition feeding structure and T-shaped slotline structure. A differential mode (DM) high-pass response and a high CM suppression level are achieved by the MTS transition feeding structure, and the function of power division is achieved by the T-shaped slotline structure. Then, by combining balanced high-pass PD and low- pass SSPP structure, a balanced FPD with a center frequency of 2.4 GHz and 3-dB fractional bandwidth of 116% is designed. The low and upper cutoff frequencies can be controlled independently, and in-band CM suppression level is above 35 dB, and the resistors are loaded for improving the isolation. Finally, the balanced FPD with compact size and high CM suppression level is fabricated and measured.