Compact Microwave Half-Wave Resonator Filters with Increased Frequency Selectivity

In this paper, we study two approaches to increase the maximum frequency selectivity and to reduce the dimensions of microstrip filters with a significantly limited number of resonators. Conducted a comparative analysis of these approaches' efficiency in the design of the filters. The possibility of combining these contradictory qualities in compact structures of highly selective microstrip filters on half-wave co-directional hairpin resonators folded into the shape of a “paper clip” is shown.