RF Electronics Chapter 7: RF Filters Page 222
2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0.
Figure 7.21. Replacement of capacitors using shunt radial stub Microstrip transmission lines.
Once the circuit schematic for the whole filter is complete, the lengths and width of the
stubs and the lengths of the inductive sections are optimised, to ensure the filter meets the
passband and the stopband specifications. As part of this, the width to length ratio of the
stubs can be changed, to increase the attenuation at particular frequencies in the stopband.
Starting with the line elements shown in table 7.1, the resulting circuit diagram of the
filter, obtained after this optimisation, is shown in figure 7.22.
Figure 7.22. Circuit schematic for the 2 GHz lowpass filter.
Figure 7.23. Frequency response of the 2 GHz lowpass filter.
RF Electronics: Design and Simulation
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