Antenna94
Junior Member level 3
Hi!
I am designing a freqency mixer and have a bit of a problem. It is a single-ended multiplier-type up-converter FET mixer, so the LO is applied to the gate while both the RF and IF signals are applied to the drain. In all the literature I read that I should short the LO and its harmonics on the drain: however, my LO signal is 2GHz and the wanted RF signal is 2.1GHz. The RF bandpass filter in my diplexer shows an open-circuit at the LO frequency and I cannot think of a method which would short the LO but not the RF which is close in frequency. Can anyone help me with an idea please?
Or is it unnecessary? I could just calculate with a 50ohm termination of the RF at the gate of the FET (being close to the LO and no filtering there) and an open-circuit at the drain at the LO frequency, and using these and the S-parameters I could adjust the impedance matching circuits accordingly.
Thanks in advance for any help!
I am designing a freqency mixer and have a bit of a problem. It is a single-ended multiplier-type up-converter FET mixer, so the LO is applied to the gate while both the RF and IF signals are applied to the drain. In all the literature I read that I should short the LO and its harmonics on the drain: however, my LO signal is 2GHz and the wanted RF signal is 2.1GHz. The RF bandpass filter in my diplexer shows an open-circuit at the LO frequency and I cannot think of a method which would short the LO but not the RF which is close in frequency. Can anyone help me with an idea please?
Or is it unnecessary? I could just calculate with a 50ohm termination of the RF at the gate of the FET (being close to the LO and no filtering there) and an open-circuit at the drain at the LO frequency, and using these and the S-parameters I could adjust the impedance matching circuits accordingly.
Thanks in advance for any help!