Auto-Tuning and Self-Calibration of High-Sensitivity Radio Frequency Interferometers

Abstract

We demonstrate a technique that automatically tunes the sensitivity of a radio-frequency (RF) interferometer with a tunable liquid attenuator by accurately changing its liquid volume. The obtained effective quality factor (QEFF) of the interferometer is up to 1×108 at ~5 GHz. The QEFF is ~100 times higher than previously reported results. When material-under-test (MUT), i.e., methanol-water solution in this work, is used for the tuning, a self-calibration and measurement process is demonstrated from 2 GHz to 7.5 GHz at a methanol concentration level down to 5×10−5 mole fraction, which is 100 times lower than previously reported results. Further investigations are needed to achieve better system stability and higher sensitivity.

Microring Distributed Sensors Using Electron Cloud Generated by Four-point Probe Sagnac Interferometer

“…Figure 5 shows the antennas' directivities. Equation (5) gives the space-time applied at the add port and equations (6 and 7) give the microring output at throughput and drop ports. The output at the throughput and drop ports are normalized using equations (8 and 9).…”

“…An interferometer is an optical device which is employed as sensors for many physical quantities. An interferometer has different configurations which are employed for sensing applications [1][2][3][4][5][6][7][8]. The Sagnac interferometer is one of the configurations of an interferometer which is the focus of this work.…”

“…time modulation signal is applied at the add port ( ) of the microring, the polarization component can be calculated and used for quantum interpretation. The space time signal is given by an equation(5) [23]. = ±…”

A Microwave Flow Detector for Gradient Elution Liquid Chromatography

“…The flow cell forms the sample-under-test (SUT) branch while the tuning branch has a digital tunable attenuator (DTA) and a phase shifter. The basic MIM working principle is described in previous work. − The introduction of DTA and computer control are essential for the proposed HPLC measurements.…”

“…In this work, we propose and demonstrate a microwave flow detector technique that is promising to address the RI detector difficulties discussed above. The detector is based on our previous work on microwave interferometers (MIMs). − In this study, an electronically tunable MIM is developed and demonstrated for HPLC measurements under isocratic and gradient elution operations. We also show the quantification of coeluted vitamin E succinate (VES) and vitamin D3 (VD3).…”