RF Mixer Basics & Selection
An RF Mixer is a non-linear component that is used to up-convert or down-convert the frequency of a signal. During upconversion, the low-frequency IF signal is mixed with the LO signal to generate an output signal with a frequency IF + LO whereas during downconversion the RF signal is mixed with the LO signal to generate a low frequency IF signal that is RF - LO.
RF Mixers are primarily used in receivers to down-convert a high RF frequency to a lower frequency which is typically easier to process. For example, a 2.4 GHz signal input to a receiver can be down-converted to 10 MHz to further process. Similarly, it is used in transmitters when up-conversion to a particular higher frequency is required.
RF Mixer Selection
When selecting an RF Mixer it is important to know the parameters that you need to specify. Below are a list of the key parameters to look out for when selecting a RF Mixer:
Type of Mixer: There are a number of mixer topologies that can be used to create a mixer. Each topology has a different set of benefits. These include double-balanced mixers, triple-balanced mixers, image reject mixers etc.
Frequency: There are three frequencies that are of importance when selecting a mixer:
- RF Frequency – This is the high frequency that is usually received by the receiver or transmitted out from a transmitter.
- LO Frequency – This is the frequency of the local oscillator (LO), it is used to up-convert the Intermedia Frequency (IF + LO) or to down-convert the RF frequency (RF - LO).
- Intermediate Frequency (IF) is the low frequency required for processing the signal in the receive chain.
Conversion Loss/Gain: This is the loss or gain in the amplitude of the signal after frequency conversion.
Isolation: This is an important parameter, RF/LO Isolation – is the measure of signal leakage from the local oscillator to the RF path and the LO/IF Isolation is the signal leakage from the LO to the IF path. The higher the isolation the better the mixer performance.
LO Drive Power: This is the signal power required by the Local Oscillator.
everything RF has listed RF mixers from the leading manufacturers. We have compiled complete catalogs from each manufacturer, standardized their data and create a parametric search tool. This mixer search tool can be used to find RF mixer products based on a specific requirement. Users can select the mixer topology, frequency and various other parameters to narrow down on a list of products.
