In this paper we present a new compact twolayers microstrip bandpass filter using multilayer crosscoupled improved interdigital-loop resonators. The filter structure consists of four resonators placed on two microstrip stack layers. The coupling between the resonators on the upper layer and the lower layer is obtained by using three coupling apertures on the common ground plane. The fullwave simulator IE3D has been employed to design the interdigital-loop resonators and to calculate the coupling coefficients between resonators of the filter. Finally, the filter has been optimized, resulting to low passband insertion loss (less than 3 dB) and high return loss (higher than 20dB) at the center frequency. By using this two-layer technique in the microwave filter design, a filter size reduction of about 50% is obtained. These features make the proposed structure suitable for compact and high-performance circuit component designs in microwave integrated circuit (MMIC).INDEX TERMS -microstrip filter, size reduction, Bandpass filter

No abstract

This paper proposes a new microstrip bandpass filter using multilayer four-pole cross-coupled open-loop stepped impedance resonators, resulting to size reduction. The filter structure consists of four resonators placed on two stacked microstrip layers, where the coupling between the resonators on the upper layer and the lower layer is obtained by introducing two slots in a common ground plane. The full-wave simulator IE3D has been employed to design the open-loop stepped impedance resonators and to calculate the coupling coefficients of the filter structure. Finally, the filter has been optimized, resulting to low passband insertion loss (less than 3 dB) and high return loss (higher than 25 dB) at the center frequency. The results from measurement agree very well with simulation expectation.

No abstract