Numerical Simulation of the Base Impedance of Long Wire Whisker Antennas

With increasing frequencies the whisker structures used to contact honeycomb Schottky diodes remain no longer thin compared to wavelength. Whereas the finite thickness and the detailed tip shape do not influence the antenna pattern very much the antenna base impedance depends on these parameters to a great extent. A good impedance matching between Schottky diode and whisker antenna is necessary to optimise mixer or detector performance and can only be achieved if the antenna impedance is known.Antenna base impedances have been simulated numerically and checked by means of scaled model measurements for several whisker shapes. The influence of further parts of the antenna environment, as for example reflectors, has also been investigated. Simulation results have been discussed and compared to theory. Simulation has been found out to be a reliable tool for the determination of base impedances of almost arbitrarily shaped whisker antennas.