In this paper, a fully integrated wideband 240-GHz transceiver front-end, supporting BPSK modulation scheme, with on-chip antenna is demonstrated in SiGe:C BiCMOS technology with f T / f max = 300/500 GHz and local backside etching option. Within the transmitter, the upconversion is provided by fundamental mixing using a modified Gilbert cell mixer driven by a multiplier-by-eight local oscillator (LO) chain. The transmitter achieves a 3-dB RF bandwidth of 35 GHz with a saturated output power of −0.8 dBm. The down converter is equipped with a mixer first architecture. The mixer is designed utilizing a transimpedance amplifier as load for enhanced noise and bandwidth performance. For dc-coupled receiver, two dc offset cancellation loops are implemented within the receiver chain. It achieves a 3-dB RF bandwidth of 55 GHz, minimum singlesideband noise figure (SSB NF) of 13.4 dB, and a gain of 32 dB with 25-dB gain control. A wideband on-chip double-folded dipole antenna and an on-board optical lens are utilized to demonstrate a wireless link achieving 20-and 25-Gb/s data rates at bit error rates (BERs) of 6.3 × 10 −6 and 2.2 × 10 −4 , respectively, across a distance of 15 cm. The transmitter and receiver consume 375 and 575 mW, respectively, which correspond to power efficiencies of 15 pJ/bit for the transmitter and 23 pJ/bit for the receiver. They occupy a silicon area of 4.3 and 4.5 mm 2 , respectively.
In this paper, the gap waveguide technology is examined for packaging liquid crystal (LC) in tunable microwave devices. For this purpose, a line based passive phase shifter is designed and implemented in a ridge gap waveguide (RGW) topology and filled with LC serving as functional material. The inherent direct current (DC) decoupling property of gap waveguides is used to utilize the waveguide surroundings as biasing electrodes for tuning the LC. The bed of nails structure of the RGW exhibits an E-field suppression of 76 dB in simulation, forming a completely shielded device. The phase shifter shows a maximum figure of merit (FoM) of 70 • /dB from 20 GHz to 30 GHz with a differential phase shift of 387 • at 25 GHz. The insertion loss ranges from 3.5 dB to 5.5 dB depending on the applied biasing voltage of 0 V to 60 V. INDEX TERMS Liquid crystals (LC's), tunable phase shifter, phased array, gap waveguide, bed of nails.
This work reports on the development of SiGe-BiCMOS technologies for mm-wave and THz high frequency applications. We present state-of-the-art performances for different SiGe heterojunction bipolar transistor (SiGe-HBT) developments as well as the evolution of complex BiCMOS technologies. With respect to different technology generations of high-speed SiGe-BiCMOS processes at IHP we discuss selected device modifications of the SiGe-HBT to achieve high frequency performances of a complex BiCMOS technology towards the 0.5 THz regime. We show the difference of high-frequency performance difference with respect to maximum achievable transit frequencies fT and oscillation frequencies fmax in comparison to RF-CMOS technologies and depict the required increase of additional process effort for the HBT-module integration for a 0.5 THz SiGe-BiCMOS technology. Moreover different high speed circuits are presented like broadband ICs for optical communication, high frequency circuits for wireless communication at 60 and 240 GHz, mm-wave radar circuits at 60 and 120 GHz as well as THz circuits operating at 245 GHz and 500 GHz for spectroscopic applications. All reviewed circuit examples are based on the discussed 130nm-SiGe-BiCMOS technologies and show their potential for a broad range of high-speed applications.
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