Microstrip dual mode elliptic filter with modal coupling through patch spacing

摘要

Disclosed is a planar dual mode microstrip filter with the coupling between similar modes on different patches governed by the spacing between the patches rather than by microstrip coupling lines between the patches. The patches are shaped to allow dual mode coupling. The materials used in building this filter were an alumina substrate with gold metalization. The filter is encased in a conducting box made from a conducting material. One advantage of the proximity coupled structure is that it reduces the number of parts, complexity and allows the filter to be realized in a smaller space than in previous dual mode designs. This filter is useful in satellite communications, radar, and cellular communications. High temperature superconductor materials can be used in a planar microstrip form.