Future submillimeter-wave and THz (300GHz-3THz) imaging applications will require low-cost portable systems
operating at room-temperature with a video-rate speed and capable of delivering acceptable sensitivity at the very low-power
consumption levels to become attractive for truly commercial applications. In particular, CMOS technologies are
of interest due to their high integration level offered at a high yield that is capable of massive cost reduction of currently
existing THz systems. It has been recently demonstrated that CMOS direct detectors achieve the performance
comparable or even superior to the today's existing classical THz devices for active imaging operating at room-temperature. So far, however, only single pixels have been used, allowing only a raster-scan operation. To address this
obstacle, we present the very initial work on a 1k-pixel camera chip with a completely integrated readout circuitry and
with a full video-rate capability at a power consumption of 2.5μW/pixel. The chip is fully compliant with an industrial
bulk CMOS technology and it is intended for active imaging applications. It exhibits a pixel pitch of 80μm, defined by a
novel on-chip wire ring antenna, and is designed to accommodate silicon hyper-hemispherical lens for a wide operation
bandwidth of at least 0.7-1.1 THz.
This paper presents a fully differential comparator that can be
used in a N bit Flash A/D converter as continuous-time sigma-delta modulator quantizer. The comparator is an extension of the dynamic comparator presented by Lewis and Gray, resulting in a 4 bit A/D. Its main advantages are : compact architecture based on MOS transistor only, without any passive components such as resistance ladder or switch capacitance, fully differential input and output voltages, operating at very low voltage. Using this comparator, a 4 bit flash A/D converter has been designed in a 0.13μm CMOS technology, under 1.2V supply voltage. It operates at 300Msample/s, suitable for over sampled data converter. The simulation shows a 3.8mW power consumption for the whole ADC.
A prototype of a 433.92 MHZRF receiver using a micro- mechanical resonator as channel-selection filter in the 2nd IF stage has been realized (94.5 kHz center frequency, 20 Hz bandwidth). A novel approach is used for managing the temperature drift of the center frequency of the micro-mechanical filter. Instead of stabilizing the filter's center frequency by complex device-level and technological modifications (bias voltage tuning, mechanical or thermal compensation), we modified the architecture of the IF stage in order to continuously adapt the IF frequency to the filter's center frequency deviations. This is achieved by periodical real-time measurements of the filter's center frequency and by then generating the appropriate second LO frequency. The measurement of the center frequency is achieved by putting the filter in an oscillating closed loop. The measured relative matching error between the 2nd IF frequency and the filter's center frequency is better than 0.005%.
A design method for high-order electro-mechanical filters that makes use of the equivalence between lumped-parameters electrical and mechanical systems is presented. Conditions for existence of the equivalent mechanical system are derived, and electro-statical coupling of micro-mechanical resonators is introduced. The application to the simulation and design of a bandpass filter with finite transmission zeros implemented in a thick-layer epi-poly silicon micro-machining technology is shown.