18 October 2012
TowerJazz and UCI demo integrated 94GHz imaging transceiver with record performance in silicon
Specialty foundry TowerJazz(which has fabrication plants at Tower Semiconductor Ltd in Migdal Haemek,Israel,and at its subsidiaries Jazz Semiconductor Inc in Newport Beach,CA,USA and TowerJazz Japan Ltd)says that researchers at the University of California,Irvine's(UCI's)Nanoscale Communication Integrated Circuits(NCIC)Labs have built a W-band(80-100GHz)2×2 focal-plane array(FPA)integrated system with record NETD(noise equivalent temperature difference)performance for passive millimeter-wave imaging using TowerJazz's SiGe BiCMOS process(SBC18H2).
TowerJazz claims that this unprecedented level of integration and performance in a silicon process can reduce the cost of millimeter-wave imaging systems.These are initially being deployed in security(cameras and scanning),medical,and automotive radar applications but,with the lower cost that silicon provides,can be applied to future consumer applications.
The imaging receiver(without antenna)achieves a measured average responsivity and noise equivalent power(NEP)of 285MV/W and 8.1fW/Hz1/2 respectively,across the 86-106GHz bandwidth,which results in a calculated NETD of 0.48K with a 30ms integration time.This represents a 1-2 orders of magnitude improvement in NEP versus other methods and demonstrations to date,a 4-10x improvement in NETD versus,for example,65nm CMOS.With antenna,the system NETD increases to 3K with on-chip antenna due to its low antenna efficiency in the W-band.TowerJazz claims that the work demonstrates the highest integration level of any silicon-based system in the 94GHz imaging band,and that the responsivity achieved is orders of magnitude higher than previous work.
TowerJazz says that,due to performance improvements and lower cost,silicon technologies such as SiGe BiCMOS have been adopted as the primary platform for the development of millimeter-wave(MMW)systems for target applications such as short-range high-data-rate wireless communications,automotive radar,sensing and imaging.Within the MMW frequency range(30-300GHz),there are propagation windows located near 35,94,140 and 220GHz,where the atmospheric absorption is relatively low.Because passive millimeter-wave(PMMW)imaging systems are capable of operating with high performance at these frequencies,they are suitable for various applications such as remote sensing,security surveillance(e.g.concealed weapon detection at the airport),non-destructive inspection for biological tissues,and industrial process control,adds the firm.Also,the non-invasive nature of passive imaging avoids any public health concerns that are present with potentially harmful active imaging methods,such as x-ray detection used in medical and security applications.
The FPA that was designed and fabricated using TowerJazz's silicon process incorporates four Dicke-type receivers representing four imaging pixels.Each receiver employs the direct-conversion architecture,consisting of an on-chip slot folded dipole antenna,a single-pole double-throw(SPDT)switch,a low-noise amplifier,a single-balanced mixer,an injection-locked frequency tripler(ILFT),an intermediate frequency(IF)variable-gain amplifier(VGA),a power detector,an active bandpass filter and a synchronous demodulator.The LO signal is generated by a shared Ka-band phase-locked loop(PLL)and distributed symmetrically to four local ILFTs.The measured LO phase noise is-93dBc/Hz at 1MHz offset from the 96GHz carrier.
"The on-going collaboration with TowerJazz to support NCIC Labs at UCI has led to design and fabrication of 40 RF and high-speed analog ICs,and has led to the completion of several projects such as Terahertz oscillators,distributed amplifiers,and fully integrated radar-on-chip,"says professor Payam Heydari,full professor of Electrical Engineering and Computer Science at UCI.
"The UCI design cleverly integrates several features needed for millimeter-wave imaging which includes on-chip frequency synthesis and local oscillator distribution.To do this at 94GHz with low phase noise is very impressive,"comments TowerJazz executive director Dr David Howard."The UCI work has shown record performance in SiGe BiCMOS as compared to other technologies such as 65nm CMOS,and demonstrates the ability to integrate millimeter-wave transmit and receive functions together,"he adds."To have such technology available,monolithically,in highly affordable 200mm wafer silicon should enable a dramatic increase in product usage and implementation,such as in the number of cameras at airports that are used for millimeter-wave imaging."
Heydari is presenting on the topic of millimeter-wave imaging at TowerJazz's 7th annual US Technical Global Symposium(TGS)at the Hyatt Regency,Irvine on 31 October 1 November.
