Application of GXSC Broadband Mixer GX5552/5553 and Amplitude-Phase Control Chip GX1000 Replacing LTC5552/5553/ADAR1000 in Satellite Modems

Modulation is the process of loading an original signal onto a high-frequency carrier, enabling the signal to meet the transmission requirements of satellite communication channels, improve transmission efficiency, and allow more information to be transmitted within a limited bandwidth. It also reduces interference during transmission, enabling long-distance communication while ensuring signal integrity even in noisy and interference-prone environments.  

Satellite communication faces numerous challenges, such as signal attenuation over long-distance transmission, susceptibility to noise interference, and disturbances from other electromagnetic signals. This article introduces the application of domestically produced broadband mixer chips/phase-amplitude control chips as replacements for LTC5552/5553/ADAR1000 in satellite modulation and demodulation.

The GX5552/5553 are high-performance passive double-balanced mixers, capable of operating in the 3GHz to 20GHz frequency range for both upconversion and downconversion applications. They are suitable for phased array radar, early warning radar, meteorological radar, and other fields. The GX5552/5553 integrate internal RF baluns and LO amplification chains, supporting local oscillator (LO) frequencies from 1 to 20GHz with a typical LO power requirement of only 0dBm. Additionally, they feature built-in IF baluns, enabling single-ended 50Ω operation for intermediate frequencies ranging from 0.5 to 9GHz. Their outstanding performance makes them a key component in signal processing for numerous communication equipment applications.

The GX1000 supports an operating frequency range from 5GHz to 18GHz, covering the C-band, X-band, and Ku-band. Its wide frequency coverage enables compatibility with multi-band satellite communications. The GX1000 integrates four receive channels, four transmit channels, and corresponding power combining/dividing networks, making it a highly integrated silicon-based beamforming chip. Both the receive and transmit channels support amplitude and phase control, with a phase accuracy of 7 bits, enabling phase control in 2.8° increments within a 360° range. The amplitude accuracy is 6 bits, supporting amplitude control in 0.5dB increments within a dynamic range of 31.5dB.

Key Performance Indicators of the GX1000 Chip:

RF operating bandwidth: 3~20 GHz

LO operating bandwidth: 1~20GHz

IF working bandwidth: DC~6GHz

Downconverter Input P-1dB: 16dBm (Typical Value)

Upconverter input P-1dB: 13dBm (typical value)

Downconversion IIP3: 27dBm (typical)

```Input IP3 (on-chip mixer): 23dBm (typical)```

Downconversion loss: 10dB (typical value)

Up-conversion loss: 8dB (typical value)

Required LO power: 0dBm (typical value)

Voltage/Current: 3.3V/146mA (typical value)

Chip size: 3mm × 2mm

Operating temperature range: -40°C to 125°C