Advanced Analog MMICs for mm-wave Communication and Remote Sensing in 0.15µm mHEMT Technology
Multi-Gigabit per second wireless communication and atmospheric remote sensing for weather forecasts are new applications in the mm-wave frequency spectra. The High Electron Mobility Transistor is an excellent technology for high frequency mm-wave applications. Its low noise and linear performance makes a 0.15 μm GaAs metamorphic HEMT technology the basis for three MMIC circuit designs at mm-wave frequencies. The wireless data traffic has increased exponentially over the last years due to more network subscribers and their fast adaptation to use high datarate mobile services. In order for the operators to evolve and accommodate higher data-rates at affordable prices, new microwave bands for point-to-point communication is a cost effective solution for increasing the backhaul capacity and deliver higher data rates to the network users. Two mm wave mixers for wideband E-band communications, specially focusing on direct modulation and demodulation solutions have been designed, fabricated and characterized. Direct modulators requires added functions such as quadrature signals and LO-RF isolation to be compatible with e.g. QAM modulated signals. Complex high performance mixers with novel solutions have been designed to cope with cost, function and performance. Since cost is a driving factor, a novel differential branchline coupler has been introduced to reduce size while maintaining function and performance. The design rely on differential modes to accomplish this, something that is common in CMOS or BiCMOS due to the lossy substrate but not in GaAs. Utilizing the properties of common and differential modes, the LO-RF isolation has been further improved by the use of a mode selective filter. The design covers the whole E-band frequency span with measured 13 dBm OIP3, conversion loss of 11 dB, LO-RF isolation >30 dB and IF bandwidth of 5GHz. Remote mm and sub-mm wave sensing in Geostationary Earth Orbit has become an alternative solution for providing more accurate short term (nowcasting) weather predications. The advantage of being in geostationary orbit is the continuous coverage over a relatively large area. One of four frequency band of interest for this is 53GHz, where a complete single chip MMIC receiver with integrated low noise amplifier, frequency multiplier and image reject mixer was designed, manufactured and measured. The Noise Figure (NF) of the receiver was measured to be 4.6 dB, with a total power consumption of 140mW, conversion gain and image rejection measured to be 10 dB and >47 dB respectively. The NF is the lowest reported for a single chip receiver at 53GHz.