Millimeter-wave frequency spectra offers invaluable bandwidth for automotive, communications, research, and other applications if those frequencies can be downconverted to lower-frequency bands for analysis and study. The model A20-MCH313 frequency downconverter from AKON provides such frequency downconversion for 12 parallel channels of mmWave signals. It leverages a common local-oscillator (LO) source for the downconversion process.
The downconverter is driven by compact hybrid microwave-integrated-circuit (MIC) modules. It performs frequency conversion of 12 signal channels across any 200-MHz frequency span from 36 to 37 GHz to a lower, output intermediate-frequency (IF) band from 335 to 535 MHz for ease of signal processing.
1. This module provides common stable LO signals for the mmWave frequency downconversion modules.
Used at lower power levels, the 12-channel downconverter’s hybrid MIC modules include a six-channel LO generator (Fig. 1) and six dual-channel, frequency-downconverter modules (Fig. 2). The LO source module works with an external reference oscillator capable of producing 9.0625 MHz at 0 dBm. It provides LO signals to the six dual-channel, frequency-downconverter modules. Each input channel of the downconverter modules includes a low-noise amplifier (LNA), an image-reject filter, frequency mixer, IF bandpass filter, and IF amplifier. The 12 input channels are identical, and all convert the same RF input band from 36 to 37 GHz to the same output IF band from 335 to 535 MHz.
2. This hybrid MIC module contains 12 channels of frequency downconversion to translate mmWave input signals to lower-frequency IF output signals.
The A20-MCH313 fixed-frequency downconverter array maintains a noise figure of 4 dB or better with nominal conversion gain of 67 dB. It can process input mmWave signals across a wide dynamic range of −87 to −55 dBm while providing 25-dB image rejection for all input signal levels.
The overall downconverter assembly measures a compact 14.0 × 8.0 × 5.8 in., including baseplate and cover with 2.92-mm female RF input connectors and SMA female output IF connectors. It’s designed for operating temperatures from +15 to +40°C—a test laboratory is an example of a typical operating environment. The downconverter assembly requires a +12-V dc bias source to power its active components.
Versions of the 12-channel frequency downconverter can be supplied for customer-defined bands at frequencies to 50 GHz, in sealed housings for a wide range of applications. The RF-to-IF conversion gain is nominally 67 dB for custom designs with better than 25-dB IF stopband rejection and −25 dBc minimum image rejection across the passband. The LO generation modules work with reference frequency input of 9.0625 MHz at a nominal input level of 0 dBm, and a “no damage” RF input levels to 0 dBm while generating an IF output dynamic range of −20 to +12 dBm.