Terahertz technology is on the verge of breaking through into major application fields such as medical technology, non-destructive materials testing, radar, security, food processing, and space. This can be attributed to the rapidly advancing developments in microelectronics.
FBH focuses on a broad spectrum of THz activities including MMIC chip design and fabrication, integrated THz detector design, integrated THz antennas, and THz device and circuit characterization. This way, FBH both advances the field of THz electronics and supports industry in developing applications that require THz electronics. 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. FBH has 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.
For frequencies beyond 1000 GHz, FBH also explores plasmonic operation and develops the related interconnect and calibration techniques scalable to these frequencies. Plasmonic operation is based on FBH’s 0.25 µm GaN HEMT process. FBH, in cooperation with the Goethe-Leibniz-Terahertz-Center, has developed detectors and investigates emitters operating in the frequency range 500 - 2500 GHz with integrated antennas.
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, FBH focuses on signal generation and amplification circuits, as can be depicted from the block diagram with potential system components. Additionally, a flip-chip module technology is available up to 500 GHz.
Ultra-broadband frequency multipliers have been designed for the G-band and D-band with a peak output power Pout = 10 dBm and broadband power operation with Pout > 5 dBm. Example multipliers are (a) a broadband doubler, 140 - 220 GHz (full G band), Pout > +8 dBm (10 dBm @ 180 GHz) together with a D-band doubler and (b) a 164 GHz BiCMOS VCO with InP doubler, Pout = 7 dBm @ 164 GHz (Best paper award EuMW 2013: T. Jensen et al: A 164 GHz Source in Hetero-Integrated InP-on-BiCMOS). Also shown is a 330 GHz heterointegrated InP-on-BiCMOS quadrupler, Pout ~ -12 dBm @ 328 GHz, harmonic suppression < -30.
FBH has developed ultra-wideband travelling-wave amplifiers (TWA) and wideband transimpedance amplifiers (TIA) with record performance. As an example, a DC-175 GHz TWA with 12 dB gain and uniform linear phase and output power is illustrated, with P1dB > 8 dBm beyond 150 GHz with a peak PAE of 6%.