Patent ID: 8604883

Claim:
A class-C power amplifier comprising: an amplifying element whose power supply voltage is expressed as Vdc and whose maximum current is expressed as Imax, a conduction angle θo of the amplifying element being less than π(rad), and load impedance of a fundamental wave being expressed as Z 1 =R 1 +j·X 1 and load impedance of a 2nd harmonic being expressed as Z 2 =R 2 +j·X 2 which are observed from a dependent current source of an equivalent circuit of the amplifying element, wherein a relationship between variables X 1 and R 1 is set to —R 1 <=X 1 <=R 1 , variable R 1 is set to R 1 =Vdc/Imax·π·{1−cos(θo/2)}/{θo/2−sin(θo)/2}, and variable X 2 /X 1 is set to X 2 /X 1 =−{θo/2−sin(θo)/2}/{sin(θo/2)−sin(1.5·θo)/3}, or each of the variables is set thereto so as to become equal substantially, and R 2 <⅓·R 1 is applied.