Figure 11

Maximum value of the Q -parameters as a function of the parasitic capacitance \(\pmb{C_{p}}\) . The circulator is matched to the external impedance of 50Ω and the matching is optimized for filling factor \(\nu = 8\). As expected, when the currents carried by the parasitic capacitances and the direct channels are comparable, i.e. \(C_{p}\approx 20~\mbox{fF}\), circulation in the reversed direction is strongly enhanced. Interestingly, for certain values of \(C_{p}\), e.g. \(C_{p}\approx40~\mbox{fF}\), circulation is equally good in both directions; thus, tiny changes in the operating frequency of the device can reverse the circulation direction.