PURPOSE: To realize the small sized multicoupler with high performance by obtaining each of length of a sender side and receiver side transmission lines based on the calculation under a specific condition.
CONSTITUTION: A transmission filter and a reception filter each being a single filter are terminated respectively by a characteristic impedance of the circuit system, the impedance of the terminated transmission filter and the impedance of the terminated reception filter with respect to the reception frequency are measured respectively, and the real part R and the imaginary part X of the measured values are used for the calculation according to equations I-V. Then each length Lm of the transmission and reception transmission lines is obtained, in which the insertion loss of the transmission reception filters when viewing from a common terminal is an extreme value. In the equations I-V, λ is a reception wavelength of a reception signal on the transmission line in the case of calculating the length of the sender side transmission line and a transmission wavelength of a transmission signal on the transmission line in the case of calculating the length of the receiver side transmission line and π is a circle ratio. Thus, the small sized multicoupler with an excellent frequency characteristic is realized.
KASAGI MASAKATSU
SAKAMOTO NOBUYOSHI
