Duplexer (Duplexer)
A duplexer consists of two filters, one for transmission (Tx) and one for reception (Rx), sharing a common node (usually an antenna). Duplexers are primarily used in frequency division duplexing (FDD) radio applications. The design objective is to ensure that the transmit filter and receive filter do not interfere with each other, and that the transmitted signal in the receive output is significantly attenuated to prevent overdriving of the receiver front end. This isolation at the transmitting frequency typically requires an isolation level of more than 55 dB.
Three Tools (Triplexer)
A tri-hybrid transceiver consists of three filters (or ports) sharing a single node (or port). The passband loading and isolation targets are similar to those of a duplexer. A common application of tri-hybrid transceivers is to combine two duplexers into one, saving circuit board space. For example, in a frequency division duplex system, a wideband filter can be used to combine two bands, thus forming a tri-filter structure.
Four-instrument (Quadplexer)
A quadriplex consists of four filters sharing a single node. Similar to duplexers and triplexers, its passband loading and isolation targets are consistent. The design of a quadriplex is more complex because it must meet the requirements of all four filters simultaneously and comply with stringent cross-isolation specifications. A quadriplex allows two bands to connect to an antenna at the same time, making it highly suitable for applications such as carrier aggregation, where a single phone may need to receive two bands simultaneously.
In terms of cross-isolation, duplexers require the transmitted signal to be significantly attenuated at the corresponding receiving frequency output, while quadriplexers require significant attenuation of the transmitted signal at both receiving outputs. This means that quadriplexers need more isolation measures to maintain separation between frequency bands. In summary, quadriplexers have more stringent isolation requirements than duplexers and are more complex.
Although duplexers, triplexers and quadruplexers may sound complicated, they play an important role in wireless communication systems. By using these multiplexer devices, effective spectrum management can be achieved to improve the performance and efficiency of wireless systems.