Design of compact broadband filtering power divider based on new coupled-line isolation network
Based on coupled dual-line and three-line structures,a design method for broadband filtering power divider(FPD)is proposed.By extending two output side lines in the coupled three-line structure as the short-circuited ones,filtering response with two transmission zeros at both sides of the passband is achieved.Meanwhile,by exploiting the extended short-circuited stubs,bandpass coupled structures can be constructed to design new isolation network,leading to good wideband isolation between output ports.For design guidance,theoretical filtering response of the three-port FPD is predicted and the impedance condition for good port-to-port isolation is analyzed according to the even-/odd-mode equivalent circuits.Then,the initial size of proposed FPD as well as the initial value of isolation resistor can be determined.For verification,an FPD prototype centered at 1.93 GHz with a 3 dB fractional bandwidth of 60.5%is designed and fabricated by utilizing the multilayer planar printed circuit and the measurement is also conducted.Results show that proposed FPD exhibits 15 dB port-to-port isolation from DC to 2.26 GHz,and the dimension of realized circuit is only 0.35λg×0.17λg.
filtering power dividerbroadbandcoupled three-lineisolation networkmultilayer printed circuitminiaturization
万方数据
维普
