Ultra-Miniaturized Wideband Input-Absorptive Bandstop Filter Based on TFIPD Technology

This brief presents the ultra-miniaturized wideband input-absorptive bandstop filters with one and three transmission zeros using the thin film integrated passive devices (TFIPD) technology. It is based on a novel T-shape structure with lumped-element resonators and one resistor chained on the input port. The basic bandstop block composed of lumped-element resonators can be synthesized by the Chebyshev reflective prototype values ( g-parameters). In order to further expand the stopband bandwidth and improve the frequency selectivity, the series inductance and capacitance resonator (SICR) is loaded on the basic bandstop block, thus resulting in two extra transmission zeros. The chained resistor on the input port is used to absorb the input-signal power. For demonstration, the one-zero and three-zero design cases operating at 5 GHz are simulated, manufactured and measured, respectively.