Oscillator-Based Reactance Sensors With Injection Locking for High-Throughput Flow Cytometry Using Microwave Dielectric Spectroscopy

Abstract

This paper presents the analysis and design of oscillator-based reactance sensors employing injection locking for high-throughput label-free single-cell analysis using dielectric spectroscopy at microwave frequencies. By injection-locking two sensing LC-oscillators with an I/Q excitation source, the measurement of the sample-induced frequency shift caused by the interaction with the electromagnetic fields is performed through phase detection with injection-strength-dependent transducer gain. Such inherent phase amplification offered by the injection locking not only relaxes the design requirement for the readout circuits but also maintains the highest rejection against common-mode errors associated with the drift of the supply voltage and the environmental parameters. To reduce flicker noise contribution, a chopping technique employing phase modulation is exploited. In addition, this paper presents a novel ping-pong chopping approach to alleviate chopping-induced dc offset. In this prototype, four sensing channels, covering frequencies between 6.5 and 30 GHz, are distributed along a microfluidic channel fabricated with standard photolithography. Measurements show that the proposed microwave capacitive sensors achieve a sub−aFrms of noise sensitivity at 100 kHz filtering bandwidth, enabling measurement throughput exceeding 1 k cells/s. The sensor prototype is implemented in 65 nm CMOS technology and consumes 65 mW at 1 V supply.

A 40-nm CMOS Complex Permittivity Sensing Pixel for Material Characterization at Microwave Frequencies

“…The chip power consumption on a 1.1-V supply was measured between 1.2 mW at 0.1 GHz and 24 mW at 5 GHz, a difference due to the fact that bridge and LO drivers are inverter-based circuits and, as such, their power consumption varies linearly with frequency. (23) and (24). ∆f = 1 kHz, IP N = −90 dBc, N F = 7.5 dB, CG = 30 dB (off-chip amplification included).…”

“…Efforts towards miniaturization of microwave permittivity sensing systems have been mainly concentrated towards CMOS implementations because of the ultimate form factor that CMOS offers. Several microwave CMOS implementations during the last years have demonstrated accurate permittivity readout [17]- [24]. Oscillator-based approaches exist, which are very narrow-band, area-consuming and limited to measurement of the real part of permittivity, thus are not suitable for implementation of a broadband permittivity sensing pixel [17], [19], [22], [24].…”

“…Several microwave CMOS implementations during the last years have demonstrated accurate permittivity readout [17]- [24]. Oscillator-based approaches exist, which are very narrow-band, area-consuming and limited to measurement of the real part of permittivity, thus are not suitable for implementation of a broadband permittivity sensing pixel [17], [19], [22], [24]. Several other implementations achieve an operation frequency range of at least a decade by employing broadband down-conversion [18], [20], [21], [23] or wide-band PLL-based architectures [22].…”

A 2.2 <inline-formula> <tex-math notation="LaTeX">$\mu\text{W}$</tex-math> </inline-formula>, <inline-formula> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula>12 dBm RF-Powered Wireless Current Sensing Readout Interface IC With Injection-Locking Clock Generation

“…For counter-based time-to-digital converter (TDC), according to [21], the frequency noise can be expressed as…”

Biological cell discrimination based on their high frequency dielectropheretic signatures at UHF frequencies

“…Currently the development of sensitive and label-free biosensors, able to handle biological cells for individual and accurate analysis, attracts many research efforts especially in the microwave community [1][2][3][4][5]. Labeling procedures are generally expensive, time-consuming and potentially cytotoxic, whereas label-free detection can preserve cell viability and enable post-analysis cell utilization.…”