RF Electronics Chapter 7: RF Filters Page 254
2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0.
Resonator 1 50 Tap = 0.487 Lr = 46.96 mm
Resonator 2 36 Tap = 0.614 Lr = 44.99 mm
Resonator 3 36 Tap = 0.426 Lr = 44.99 mm
Resonator 4 36 Tap = 0.614 Lr = 44.99 mm
Resonator 5 50 Tap = 0.487 Lr = 46.96 mm
Figure 7.70. Filter layout for initial tap values.
Entering those values in the Cadence AWR DE circuit schematic of the filter, results in
the initial filter layout shown in figure 7.70, with the corresponding frequency response
shown in figure 7.71. To highlight differences between the 750 MHz and 1250 MHz,
corner frequency specifications and frequency-response obtained from the computer
simulation, an optimisation mask is superimposed on figure. 7.71. In addition, an
optimisation mask for a –1 dB attenuation from 780 MHz to 1220 MHz is shown. It can
be seen that the design procedure results in a filter that has a bandwidth that closely
matches the design specifications, but whose centre frequency is 3.5% low. This
difference is due to the end effect of the open circuit resonators not being taken into
account in the above calculations.
Figure 7.71. Frequency response for initial wideband filter.
RF Electronics: Design and Simulation
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