InP HBT Transceivers
Electronic component and system design
FBH has established a joint laboratory Goethe-Leibniz-Terahertz-Center with Goethe University Frankfurt and foundry activities with Leibniz-Institut für innovative Mikroelektronik (IHP). FBH operates an indium phosphide (InP) double heterojunction bipolar transistor (DHBT) transferred-substrate (TS) process and an InP-on-BiCMOS DHBT process. They reach cut-off frequencies around 500 GHz today and are being extended to yield over 700 GHz. We have demonstrated nonlinear active integrated circuits (MMIC) up to 300 GHz as building blocks for system-on-chip solutions, using heterogeneous integration with silicon and diamond materials.
MMIC design at FBH is based on a MMIC design kit with active and passive elements and proprietary large-signal HBT device models including thermal effects. InP HBT technology offers operation at voltages up to 3.5 V and high frequencies with excellent phase-noise properties. Therefore, we focus on signal generation and amplification circuits. Additionally, we have demonstrated flip-chip transitions up to 500 GHz.
Realized InP-DHBT MMIC circuits for communication and radar applications at frequencies > 100 GHz
Signal generation
Low noise oscillators in the range 100 GHz - 500 GHz have been designed, realized and characterized. Our fundamental and harmonic oscillators exhibit excellent DC-to-RF efficiency, high output power and low phase noise.
Example of harmonic (3rd harmonic) oscillator at 290 GHz with output power of -8.5 dBm, 0.5% DC-RF efficiency and 246 GHz source realized with BiCMOS VCO and InP tripler.
Frequency multipliers
Broad-band MMIC frequency multipliers up to 300 GHz have been designed and realized. These deliver output powers reaching Pout = 10 dBm. We have realized ferquency doublers, triplers, and quadruplers.
As an example, a frequency doubler at G-band (140 GHz - 220 GHz) exhibits an output power of Pout > 5 dBm for the overall band.
Power amplifiers
The aim for the MMIC power amplifiers is to achieve an output power of Pout > 20 dBm over a bandwidth >10 GHz with PAE > 15% at D-band. At 300 GHz we have developed power amplifiers with output power levels approaching 10 dBm.
Heterointegration InP-on-BiCMOS MMIC
InP-on-BiCMOS heterointegrated MMIC is employed to realize signal generation, frequency conversion, and amplification.
As an example we demonstrated a signal source at 246 GHz with BiCMOS VCO and InP tripler with an output power of Pout ~ -2 dBm, harmonic suppression > 25 dB, und and a phase noise of -85 dBc/Hz @ 1 MHz as well as a frequency converter with a BiCMOS VCO and an up-conversion mixer in InP technology for W-band radar applications.
The goal of the overall project is to realize a system demonstrator of an imaging MIMO radar sensor with modular system architecture, which could be flexibly mounted at different points on a satellite. Another goal is to improve the compactness of the individual transmitters and receivers so that even small satellites can be equipped with several imaging modules. The special feature of the MIMO concept here is the simultaneous operation of all transmitters and receivers creating a synthetic aperture. The work includes InP DHBT-MMIC technology for fully integrated transceiver front-ends in the W-band. These transceiver modules are to be assembled into ultra-compact system-in-package subsystems using flip-chip technology.
The goal of the TERAWAY project is to build a comprehensive (fronthaul and backhaul) 5G infrastructure for THz data transmission to and from drones and balloons. The unmanned aerial vehicles will provide 5G and 6G connectivity for large events and sporting events with very high local data traffic.
In the BMBF-funded project T-KOS, the technological competencies for communication and sensor technology within the Research Fab Microelectronics (FMD) are combined and extended by competencies of the Fraunhofer ITWM in the field of signal processing. This will enable cross-institutional system solutions for terahertz communication and sensor technology, wireless radio transmission, non-destructive testing technology (NDT), spectroscopy, and contactless inline measurement technology as an offer to industry. In particular, the following milestone relevant to the work at FBH will be achieved: industrial-grade, multistatic terahertz imaging system (line scan camera) for real-time non-destructive monitoring of production processes at 300 GHz. The goal is scalable heterointegration of silicon germanium (SiGe) and indium phosphide (InP) chips. Previous systems use expensive and discrete components that are unsuitable and not scalable for industrial applications.