Compact microwave elliptic function filter using novel microstrip meander open-loop resonators

A new type of microwave elliptic function bandpass filter using microstrip meander open-loop resonators is proposed. It is shown that the new filter structure is small and allows nonadjacent electric and magnetic couplings to be realised and adjusted. A four-pole filter of this type has, for the first time, been designed and fabricated. The filter is very compact, occupying a circuit size of about a quarter-wavelength by a quarter-wavelength at a midband frequency of 1.47GHz. Both the simulated and measured results are presented.