Diplexer for Dual-band Wi-Fi Applications

A diplexer comprising:

• a first port;
• a first filter circuit coupled to the first port, and configured to provide a first signal path for a first radio frequency (RF) signal, the first filter circuit comprising:
• a first tunable resonant circuit configured to tune a first transmission zero corresponding to a first frequency multiplication of the first RF signal;
• a second port coupled to the first filter circuit;
• a second filter circuit coupled to the first port, and configured to provide a second signal path for a second RF signal, the second filter circuit comprising:
• a second tunable resonant circuit configured to tune a first transmission zero corresponding to a first frequency multiplication of the second RF signal;
• and
• a third port coupled to the second filter circuit;
• wherein the first frequency multiplication of the first RF signal corresponding to the first filter circuit is a fourth harmonic of the first RF signal.