Planar Filter Technology For Millimeter Wave Applications

The advent of fifth generation (5G) communications brings an increased interest in Millimeter Wave (mmWave) technologies. One of the biggest technology challenges engineers face with 5G is how to implement sufficiently high-performance RF filtering in mmWave applications. Given the frequencies involved a distributed element planar approach, such as using Microstrip or Stripline, is often ideal for constructing resonators and filters.

Planar Filter Overview
Planar filters are manufactured by creating flat 2D resonators with patterns of strip elements on a dielectric substrate. Depending on the filter topology, Planar filters can offer a high quality factor (Q) and a reasonable approach to achieving performance in a small footprint. The structure of Planar filters is similar to a printed circuit board, but with the key distinction that the metal conductor patterns printed on the solid dielectric substrate are there to create resonators rather than just interconnects.