Masaaki Fuse

High-dynamic-range measurement of millimeter-wave amplifier using 140-GHz fundamental mixer

Analysis and measurement of radio signals above 60 GHz requires connection of an external mixer to a commercial spectrum analyzer. In this setup, in addition to the actual frequency components, unwanted multiple response generated by the external mixer are also observed simultaneously, making it difficult to observe the actual frequency components. Furthermore, the signal components are easily buried by measuring instrument noise due to the poor mixer conversion efficiency, causing difficulties in observing very low power signals. This paper presents the results of some tests and trials of a 140-GHz fundamental mixing test system with potential for high-dynamic range measurements and small unwanted multiple response compared to measurements using previous harmonic mixers. The results are the first to demonstrate a 20-dB or higher dynamic range as well as excellent wideband suppression of multiple response compared to measurements using harmonic mixers.

Over 100 GHz millimeter-wave spectrum measurement system with pre-selector

The recent start of R&D into Wireless Personal Networks (WPAN) and millimeter-wave wireless systems is creating an urgent need for development of a spectrum analyzer supporting accurate measurements in the frequency band above 100 GHz. However, there is no spectrum analyzer with a built-in pre-selector supporting spectrum analysis of wireless signals above 67 GHz. Such measurement is made generally by connecting a harmonic mixer or Block Down converter externally to a spectrum analyzer. In this case, generated unwanted signal components (spurious responses) are often seen during measurement, making it difficult to monitor the original signal components. This paper proposes development of a millimeter-wave spectrum measurement system incorporating a pre-selector function for wide dynamic range measurements with minimum unwanted signal components. We present the results of investigation into a prototype of the proposed system. We also measured a 120 GHz QPSK modulation wave to demonstrate the effectiveness of this system with pre-selector.

300-GHz band millimeter-wave spectrum measurement system with pre-selector

Recent research is progressing into development of systems using frequency bands above 100 GHz, which is effective for short-range and broadband communications. At spectrum analysis in these frequency bands, generally either a down converter or a harmonic mixer is used to convert the frequencies to a band that can be observed by a conventional spectrum analyzer. In this case, unwanted signal components (Spurious responses) are often seen during measurement. Non-linearity in the measurement system generates harmonic components due to the input signals. Therefore, these harmonic components are mixed at spectrum observation and it becomes difficult to distinguish one from the other. To overcome this problem, we have constructed a 300-GHz band spectrum measurement system using a novel pre-selector design and describe the results of evaluation using this system.