Fig 1 . Topology schematic of the duplexer with resonating frequencies, coupling coefficients and the external Q. (Black solid circle represent the resonators. Numbers next to the lines connecting the circles represent coupling coefficients or external Q . Solid line segments with arrows: FDC the pair \(\frac{k_{0i,j}}{C_{i,j}}\).)
The diplexer simulation model is shown in Fig. 2, whose dimensions are 55mm×21mm×19mm, the simulation response and synthesis response are matched well as shown in Fig. 3.