The invention discloses a method for designing a universal
ultra wideband impedance matching network. A
wideband matching network is added at the
radio frequency input end or the
radio frequency output end of a
radio frequency circuit, and can be one of a T-type matching network, a Pi-type matching network and a
hybrid matching network; elements in the matching network can be inductors or capacitors; the input
reflection coefficient S11 or the output
reflection coefficient S22 of the designed radio frequency circuit is shown in a
Smith chart; an S11 curve or an S22 curve changes in the
Smith chart by serially or parallelly connecting the inductors or the capacitors in the matching network; and the two curves finally completely fall into a -10dB
impedance matching circle, so that the radio frequency circuit realizes
impedance matching within an
ultra wideband frequency band. An optimal
ultra wideband impedance matching network can be conveniently designed by the method; and taking a
low noise amplifier (LNA) as an example, for an optionally given LNA structure, an optimized matching network can be acquired by inserting one or more inductors or capacitors into an input and output matching network. In the process of designing the matching network, the positions of the
reflection coefficient curves in the
Smith chart are adjusted by adjusting the connecting mode and the sizes of the elements, and the reflection coefficient curves can move into reflection coefficient circles such as -10dB and the like in the range of an overall designing
frequency band, so that the aim of accomplishing the good impedance matching in a wide
frequency band range is fulfilled.