Patent ID: 8106847

Claim:
A communication circuit, comprising: a nonresonant antenna; and an impedance-matching circuit connected to the nonresonant antenna, wherein the impedance-matching circuit has a transmission line, electric length θ 0 and characteristic impedance Z 1 of the transmission line are calculated by equation (eq1) using external Q Q e1 , reactance X a , and radiation resistance R a of the nonresonant antenna, and θ 0 = 1 2 ⁢ Sinc - 1 ⁡ ( X a 2 ⁢ Q e ⁢ ⁢ 1 ⁢ R a - X a ) , Z 1 = X a ⁢ tan ⁢ ⁢ θ 0 . ( eq ⁢ ⁢ 1 )