RF Electronics Chapter 5: Frequency Mixers Page 167
2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0.
If Frater-Gilbert Cells are used then the mixers inputs need to be connected to the LO and
RF signals for down conversion and to the LO and IF signals for up conversion.
Examples of Commercial Active Mixers
Many manufacturers produce active mixers for use in commercial equipment. In
particular, mixers for use in mobile and cordless phones, wireless LANs and similar
consumer devices are readily available.
The LTC5588-1 IQ mixer shown in figure 5.96 is used as an up-converter for mobile
radio applications. This mixer uses Frater-Gilbert cells for the mixers. An IQ mixer allows
the required RF output signal to be produced, without the need to filter out unwanted
sidebands. The LTC5588-1 has a minimum image rejection of -27 dBc. An I and Q signal,
up to 430 MHz can be used, to produce a quadrature modulated RF signal from 200MHz
to 6GHz, with an output power up to -1.9 dBm. In the 900 MHz mobile/cellular phone
band, the typical image rejection is -45 dBc and in the 1.8 and 2.1 GHz bands, the typical
image rejection is -55 dBc. The mixer performance satisfies all the G2 to G4 mobile radio
standards. These devices are aimed at base-stations, point-to point microwave links,
Digital TV and DAB modulators and military radios. GaAs Microwave Monolithic IC's
(MMIC) are used for most commercial mixer applications.
Figure 5.96. LTC5588-1 typical application (top) and simplified schematic for one channel [20].
RF Electronics: Design and Simulation
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