An analysis of an N-port microstrip planar disk device with an arbitrarily located short circuit post of arbitrary radius

An analysis technique is presented which allows the performance of a multiport microstrip planar disk device with an arbitrarily located internal short circuit (S/C) post of arbitrary radius to be predicted. The analysis approach does not rely on the determination of eigenvalues and yields analytical expressions which are ideal for CAD implementation. The technique allows the electromagnetic fields at the periphery of the disk to be dramatically altered by an appropriate choice of post size and offset. Since the operation of N-port devices is dependent on the peripheral fields, this technique offers a potentially very powerful design tool for the production of planar disk devices