Lumped triple-frequency impedance transformers

Presented is a lumped triple-frequency impedance transformer for impedance matching between real loads and real sources. A traditional L-network is used in this transformer with lumped circuit blocks realising needed susceptances and reactances at specified frequencies. Design formulas for lumped elements are deduced. A triple-frequency impedance transformer is designed to realise impedance matching at 0.225/0.425/0.625 GHz. Compared simulation and measurement results have demonstrated good matching at the required frequencies. The proposed network has the advantage of more compact dimensions compared to distributive solutions, and is thus suitable for VHF/UHF applications.