Enhanced duplexer with higher isolation and better linearity

As the number of mobile devices is increasing at an exponential rate, the capacity of conventional base station will not be able to cope with the growth of mobile data. Small cell comes to the stage as the key solution to this problem. Since the frequencies get closer in LTE Advanced network [1], a higher isolation between the Rx and Tx is necessary to preserve the receptor sensitivity. Nowadays, for a multi-band small cell, the SAW duplexer with a small size is more suitable than the large ceramic duplexer. However, the SAW duplexer can't guarantee a sufficient isolation. Our enhanced duplexer based on SAW component improves this isolation by the noise cancellation between Rx signal and Tx signal with a small size and cheap price. As a result, the isolation between Rx and Tx signal can reach −75dB as the typical value, and −60dB as the minimum value in the passband. And the non-linearity of this enhanced duplexer has gained 6dB compared to a stand-alone duplexer.