LTCC (low temperature co-fired ceramic) miniaturized duplexer

An LTCC miniaturized duplexer comprises an LTCC base body layer 1. A duplexer circuit structure is formed on the LTCC base body layer. The duplexer circuit structure is composed of a low-pass filter circuit 2 and a high-pass filter circuit 3. The low-pass filter circuit comprises inductors L1, L2 connected in series between a common input port P1 and a low-frequency output port P2. A capacitor C1 connected with a grounding port is connected between every two adjacent inductors L1, L2. The high-pass filter circuit 3 comprises capacitors C2, C3, C4 connected in series between the common input end P1 and a high-frequency output port P3. An inductor L3, L4 connected with the grounding port is connected between every two adjacent capacitors C2, C3, C4. The effects of suppressing a parasitic passband on the low-pass duplexer and optimizing out-of-band rejection of the high-pass duplexer are achieved by using the parasitic parameters of all components through reasonable three-dimensional layout.