Patent ID: 7710217

Claim:
A matching circuit comprising: a main-matching block for performing impedance matching; and a sub-matching block for performing impedance matching; wherein the main-matching block and the sub-matching block are connected in series with each other in a signal path of a radio-frequency signal, wherein the sub-matching block comprises: a series matching block connected in series with the main-matching block; and a parallel matching network connected to the series matching block on the side opposite from the main-matching block, and also connected in parallel with the signal path; wherein the parallel matching network comprises: a first parallel matching block having one end connected to the series matching block; a second parallel matching block having one end connected to the other end of the first parallel matching block; and a third parallel matching block having one end connected to a connection point between the first parallel matching block and the second parallel matching block, wherein the first parallel matching block is configured to cause a connection point with the series matching block to be in an open state for a radio-frequency signal of a first frequency, wherein the second parallel matching block is configured to cause the connection point with the first parallel matching block to be in a shunted state for the radio-frequency signal of the first frequency, wherein the main-matching block and the series matching block are configured so that an impedance at one end of the series connection matches the impedance of the other end thereof at the first frequency, and wherein the main-matching block and the sub-matching block are configured so that the impedance at one end of the series connection matches the impedance of the other end thereof at a second frequency which is different from the first frequency.