Accurate displacement measurement is critical for many applications. Recently, a variety of radio-frequency-based linear displacement sensing techniques were introduced. However, the application of the previously proposed techniques was either not fully demonstrated towards realizing the sensor and/or they were limited in measurement range to less than 4 cm. This paper introduces a fully characterized wide-range radio-frequency-based contactless linear displacement sensor. The sensor consists of a short-circuited 50 Ω microstrip line and a movable current-sensing resonant probe. The probe accurately measures the sinusoidal magnetic field distribution along the short-circuited transmission line from a certain distance above it. The measured normalized field values are mapped to displacement using the inverse of the sinusoidal function in the post-processing stage. The proposed technique is comprehensively validated using simulations and measurements of a compact sensor prototype operating at 727.5 MHz. Furthermore, the merits of the proposed sensor compared to the widely-accepted linear variable differential transformer (LVDT) displacement transducer are highlighted herein. The metrological characterization of the proposed sensor shows that it offers a very wide dynamic range of 68 mm with a standard deviation of the estimation error of less than 0.09 mm (0.13% of the full range). It is also demonstrated that the proposed sensor outperforms the commercial LVDT transducer in terms of overall displacement measurement accuracy. In general, the proposed sensor is scalable and has a theoretical dynamic range of λ/2 making it suitable for a wide range of applications.

In the emerging world of near-field Internet of Things (NF-IoT), small footprint and energy efficient wireless sensor nodes are essential components. This brief presents a V-band transceiver for NF-IoT without the conventional low noise amplifier, mixers, power amplifier, and phase-locked loop building blocks. Also, there are no external components except a battery or energy scavenger. The choice of V-band enables a small footprint and is conducive to low-power and low energy/bit. The receiver has a low-power, on-off keying detection circuit, while the transmitter is an amplitude-redistribution cross-coupled oscillator with on-chip resonator, quenched by the transmit data. The transceiver has an integrated antenna shared by the transmitter and the receiver. The design, realized in the GlobalFoundries 65-nm low-power enhanced CMOS process, occupies 2.75 mm ² of chip area and consumes 52 μW in receive mode and 1 mW (10 μW @ 1% duty cycle) in transmit mode with a data rate of 100 kb/s. For a transmitter power of -10 dBm, the receiver sensitivity is -42 dBm for a BER of 10 ^-3 .

The integration of antennas in composite structures is gaining popularity with advances in wireless communications and the ever-increasing demands for efficient smart structures. Efforts are ongoing to ensure that antenna-embedded composite structures are robust and resilient to inevitable impacts, loading and other external factors that threaten the structural integrity of these structures. Undoubtedly, the in situ inspection of such structures to identify anomalies and predict failures is required. In this paper, the microwave non-destructive testing (NDT) of antenna-embedded composite structures is introduced for the first time. The objective is accomplished using a planar resonator probe operating in the UHF frequency range (~525 MHz). High-resolution images of a C-band patch antenna fabricated on an aramid paper-based honeycomb substrate and covered with a glass fiber reinforced polymer (GFRP) sheet are presented. The imaging prowess of microwave NDT and its distinct advantages in inspecting such structures are highlighted. The qualitative as well as the quantitative evaluation of the images produced by the planar resonator probe and a conventional K-band rectangular aperture probe are included. Overall, the potential utility of microwave NDT for the inspection of smart structures is demonstrated.

This paper presents a 160 GHz, D-band, low-noise amplifier (LNA) and a D-band power amplifier (PA) implemented in the Global Foundries 22 nm CMOS FDSOI. The two designs are used for the contactless monitoring of vital signs in the D-band. The LNA is based on multiple stages of a cascode amplifier topology with a common source topology adopted as the input and output stages. The input stage of the LNA is designed for simultaneous input and output matching, while the inter-stage-matching networks are designed for maximizing the voltage swing. The LNA achieved a maximum gain of 17 dB at 163 GHz. The input return loss was quite poor in the 157–166 GHz frequency band. The −3 dB gain bandwidth corresponded to 157–166 GHz. The measured noise figure was between 7.6 dB and 8 dB within the −3 dB gain bandwidth. The power amplifier achieved an output 1 dB compression point of 6.8 dBm at 159.75 GHz. The measured power consumptions of the LNA and the PA were 28.8 mW and 10.8 mW, respectively.