Ka / C-band Up And Down Frequency Conversion Components Research

Millimeter-wave transceiver is the key component of millimeter-wave systems such as millimeter-wave communication, radar, remote sensing, electronic countermeasures, etc. As the core components of the transceiver, the up-converter and down-converter plays a great role in the whole system.In this thesis, a set of up-converters and down- converters have been designed and fabricated. According to the user's requirement, the gain ripple of the up-converter is no more than 1.2 dB with 12dB gain. As for the down-converter, its noise figure is less than 3.0dB, the gain more than 60dB and controllable, the two-tone (IMD3) is no more than -55dBc when the input power is -78dBm.Based on the theory of converter, the indexes of the converter were analyzed, and finally the feasible scheme was chosen. In our scheme, the up-converter was divided into a local oscillator module, an IF amplification module and an up-converter module so that the scheme could be adjusted conveniently. Firstly, the local oscillator signal was generated when the reference signal was frequency-multiplied, amplified and filtered through local oscillator module. Then, after the input signal in C-band was amplified through IF amplification module and injected into up-converter module to be mixed with the local oscillator signal, the Ka-band signal was generated. As for the down-converter, it was divided into a local oscillator module, an IF amplification module and a down-converter module. Its operating principle is similar to that of the up-converter. After the input signal in Ka-band was amplified and injected into down-converter module to be mixed with the local oscillator signal, the C-band signal was generated. Then C-band signal was further amplified and filtered through IF amplification module whose gain is controlled.The measured results show that the gain ripple of the up-converter in Ka-band is no more than 1.2 dB with 12dB gain over the 300MHz frequency band, and spurious signals are less than carrier 70dB in the band and 50dB out of the band at the input power of -15dBm. As for the down-converter, the measured results are that the noise figure of the down-converter whose output is in C-band is less than 3.0dB, the gain ripple is no more than 1.0 dB with 60dB overall gain over the 800MHz frequency band, spurious signals are less than carrier 70dB in the band and 55dB out of the band at the input power of -45dBm. When the input power is -78dBm, its two-tone (IMD3) is -55dBc. The actual dimensions of the down-converter are 114mm×66mm×32mm, which is very compact.