EVALUATION OF ACTIVE ADMITTANCE OF RADIATING APERTURES FOR THE PURPOSE OF PERFORMANCE ANALYSIS IN A DYNAMIC ENVIRONMENT

摘要

It is evident that almost all the electronic instruments, and systems do experience unwanted interference from external sources and In some cases it may prove disastrous. It may so happen that a particular configuration on the body of or within the instrument acts as a single element or an array of similar elements in which case it can be treated as an antenna problem in the receiving/ transmitting mode.rnIn this paper, it is aimed at evaluating the active/input admittance of any particular element in an array through the evaluation of self/mutual admittance of/ between elements which gives an idea of the contribution of that particular element towards causing or receiving interference.rnThe evaluation of self/ mutual admittance is carried out, in the transmission mode, tor the present, for the case of two identical rectangular waveguide radiating apertures backed by an infinite ground plane using method of moments (MOM) [1] and plane wave spectrum approach. Assuming that only one of the apertures is excited and that too by a y-directed electric field of TE_(10) mode, the boundary conditions are found out by matching the transverse component of the magnetic field at bothrnapertures and the magnetic field is calculated from the consideration of the exciting electric field present there. Using the principle of superposition, the boundary conditions on both the apertures in terms of the incident, internal and external x-directed magnetic flelds are evaluated. Following MOM, the reflection coefficient and transmission coefficient or coupling are evaluated. Once these parameters are known, the Y-matrix can be obtained [2.3]. Then the active admittance is obtained by knowing the corresponding excitations of an array and the self/mutual admittance by using element by element approach. It may be noted that the magnetic field boundary conditions in the two cases (transmission and receiving modes) are going to be different.