Comment on "A new procedure for calculating varactor Q from impedance versus bias measurements" [with author reply]

The above-mentioned paper by E.W. Sard [ibid., vol. MTT-16, pp. 849-860, October 1968] claims rigor in the procedure. Although Sard mentions the possibility of variable resistance in the varactor, he does not discuss completely the effects this might have on his analysis, and the commentor (N. Houlding) contends that the reason why "(previously) losses in the external transformation circuitry must be either neglected or nonrigorously corrected for" is that the assumption of constant resistance is not justified. The commentor thinks that the problems of circuit loss and variable resistance can not be attacked independently; and, in particular, that there is no justification for assuming the varactor will not contain loss terms which will simulate the behavior of losses in a matching network. The commentor believes it is misleading to imbed the varactor in a circuit which is not the minimum-loss form and to perform an analysis assuming that the varactor resistance is constant. Houlding\´s detailed argument is provided. In replying, the original author (Sard) states that subject to the assumed equivalent circuit described in his Fig. 1, he still believes the method described to be completely rigorous.