This paper presents a 60 GHz phase shifter, based on a coplanar waveguide (CPW) transmission line, loaded with ferroelectric hafnium zirconium oxide (HZO) variable metal-insulator-metal (MIM) varactors, developed for the back-end-of-line (BEoL) on-chip integration. Using the measured data of capacitance-voltage (C-V) characteristics of HZO and implementing the method-of-moments simulation, it was shown, that by changing the bias voltage between 0.95 and -3 V, the device shows a phase shift of 111° and a minimum insertion loss of -5.84 dB at 60 GHz. The chip area of the device is 0.206 mm 2 , making it the smallest among non-CMOS phase shifters.

In this paper, a comprehensive analysis on small-signal modeling of mm-wave transistor in 22nm FDSOI technology is presented. The model is constructed based on experimental S-parameters up to 110 GHz of a 22FDX® thick-oxide n-MOSFET and analytical parameter extraction approach. The non-quasi static effect is addressed thoroughly in the equivalent circuit model for high frequency validity. The bias-dependent series source and drain resistances are considered to account for the overlap regions between the gate and the highly doped source/drain regions. In addition, a simple RC network is included at the output to model the innegligible substrate coupling at mm-wave frequencies. Excellent agreements between model prediction and measurement are observed in the interested bandwidth for various bias conditions.

This paper presents a tunable 60 GHz band-pass filter, based on a coplanar waveguide (CPW) transmission line, periodically loaded with ferroelectric Hafnium Zirconium Oxide (HZO) variable metal-ferroelectric-metal (MIM) capacitors (varactors), developed for back-end-of-line (BEoL) integration. Derived from the nonlinear capacitance of hafnium zirconium oxide and implementing the method-of-moments simulation, it was shown, that with changing the bias voltage between 0.95 and -3 V, the filter’s center frequency can be tuned between 60.5 and 69,7 GHz, respectively. Hereby, a minimum insertion loss of -3.3 dB is realized. The chip area of the filter is only 0.062 mm 2 , making it the smallest among tunable V-band filters.

This paper presents two D-band frequency quadruplers (FQs) employing different circuit techniques. First FQ is a 129–171-GHz stacked Gilbert-cell multiplier using a bootstrapping technique, which improves the bandwidth and the conversion gain with respect to the conventional topology. Stacked architecture enables current reuse for the second frequency doubler resulting in a compact and energy-efficient design. The circuit reaches 3-dB bandwidth of 42 GHz, which is the highest among similar reported quadruplers. It achieves 2.2-dBm saturated output power, 5-dB peak conversion gain, and 1.7% peak DC-to-RF efficiency. The stacked FQ occupies 0.08 mm2 and consumes 22.7 mA from 4.4-V supply. Second presented circuit is a transformer-based injection-locked FQ (T-ILFQ) employing an E-band push–push voltage-controlled oscillator (PP-VCO). The VCO is a self-buffered common-collector Colpitts oscillator with a transformer formed on emitter inductors. Proposed configuration does not reduce the tuning range of the VCO, thus providing wide locking range and high sensitivity with respect to the injected signal. The T-ILFQ achieves 21.1% locking range, which is the highest among other reported injection-locked frequency multipliers. The peak output power is −4 dBm and the input sensitivity reaches −22 dBm. The circuit occupies 0.09 mm2 and consumes 14.8 mA from 3.3-V supply.

This paper for the first time prototypes and compares the homodyne and heterodyne terahertz dielectric sensors for lab-on-chip applications. The homodyne sensor consists of a multiplier chain, a balun-based power divider, an on-chip transducer, and IQ mixers. Differently, the heterodyne sensor requires an additional multiplier chain; however, it waives one mixer and a power divider, leading to reduced losses and alleviated power consumption. Fabricated using 0.13 µm SiGe BiCMOS technology, the homodyne and heterodyne sensors take 4 mm 2 and 5.2 mm 2 , and consume 400 mW and 499 mW, respectively. By experiments, both designed homodyne and heterodyne sensors can effectively sense the dielectric parameters of the samples. Moreover, the heterodyne sensor can address the DC offset issues with merely 99 mW additional power.

This paper presents a high-integration miniaturized dielectric spectroscopy system for sensing the change of permittivity at 240 GHz in the SiGe BiCMOS technology. The sensor features a transducer with a resonator to perform bandpass frequency response, whose complex value of S21 is varied with the permittivity of the sample under test. This variation can be detected and recorded as the change of amplitude and phase of the 240-GHz in-phase and quadrature direct conversion mixer. An external 30-GHz source is employed with cascade frequency multiplier chain to deliver a signal through the system with a wide tuning range of 215–245 GHz. An additional probe is employed to carry the sample and implement chip measurements on the probe station. The sensing function of this system is performed with the leaded wire as a metallic sample to be placed on the top of the transducer. Based on the measured dc output voltage changes, the calculated magnitude and phase of IQ signal in the 215–245-GHz range are used to estimate the complex permittivity change of MUTs. This dielectric spectroscopy system is also suitable for sensing the complexy permittivity change at higher frequencies in the future terahertz Lab-on-Chip measurements.

This paper presents two scalable resonator-based transducers (RBTs) at terahertz (THz) frequency range to realise THz spectroscopy for dielectric sensing. First, the design of 0.24 THz RBT is described by scaled a 0.12 THz sensing structures which utilises a wavelength-long closed-ring resonator to place inside of the Coplanar stripline (CPS) to make a high-selective bandpass response and combines with short-ended strips to create the bandstop behavior. Its scattering parameter can have a very large magnitude change and resonance frequency shift for the loaded samples. Next, a ring structure is also presented to implement 0.48 THz sensing by scaled a low frequency RBT, which employs ring resonator with an asymmetrically loaded stubs to perform a high analytic sensitivity and selectivity for loaded samples. Both presented scalable transducers, possessing the high integration capability of silicon circuits, are proved to be the promising employments in THz spectroscopy.

This paper presents a 3-stage differential cascode power amplifier (PA) for 109–137 GHz applications. At 120 GHz the circuit delivers 16.5 dBm saturated output power with 12.8 % power-added efficiency (PAE) without using power combining techniques. The chip was fabricated in 130 nm SiGe BiCMOS technology offering heterojunction bipolar transistors (HBT) with f T /f max of 300/500 GHz. The PA consists of three stages optimized accordingly to the design goals. The first stage operates in class A to provide high gain while the two following stages are biased in class AB and deep class AB in order to increase the efficiency. The circuit draws a maximum current of 100 mA from 3.3 V and 4 V supplies. It occupies only 0.24 mm 2 chip area excluding baluns and bondpads, which makes it attractive for future power combiners. The presented amplifier is suitable for radar applications, that require a high dynamic range.

A balanced RF rectifier is proposed to replace terminations in microwave circuits and thus to recycle the otherwise dissipated power in resistances. In order not to degrade the performance of the original circuits, a balanced configuration is adopted because it minimizes the variation of input impedance of the rectification circuitry. This approach achieves good input reflection coefficient over a large dynamic range and operating frequencies. The highly efficient energy recycler is composed of a 3 dB quadrature coupler and two identical RF rectifiers. The impact of amplitude and phase imbalances of the transfer characteristics of the coupler is discussed. Furthermore, an arbitrary-port-resistance coupler is studied to replace non-50- Ω terminations. The experimental verification demonstrates that the proposed circuit provides an input reflection coefficient of better than −15 dB from 2.2 to 2.5GHz over different input power levels. The measured peak RF-to-dc efficiency is 74.9% at 2.34 GHz with S11=−24dB . The proposed balanced rectifier thus significantly improves S11 over existing rectifiers and is therefore suitable for replacing resistive terminations in a large variety of circuits.

This paper presents a highly selective integrated dielectric sensor with read-out circuit at 240 GHz in SiGe BiCMOS and back-side etching technology. The sensor features with a resonator to perform bandpass frequency response which varied in accordance to the dielectric change of the sample under test. This variation can be sensed and recorded as the change of output voltage of an integrated 240 GHz IQ receiver. The demonstration of aforementioned function is verified by measuring the output of mixer when a sample is placed over the resonator.

This paper presents the concept and measurements of a new microwave rectifier based on the time reversal duality of power amplifiers. It is shown that the proposed rectifier can simultaneously provide high efficiency at large input power range over much more improved bandwidth compared to the conventional rectifier from time reversal duality. It is also reported that the proposed rectifier allows reconfiguration of the efficiency at input power range without placing the tunable elements. A 10 W wideband power amplifier with 79%drain efficiency at 1.85 GHz is used to validate the concept. By making the gate bias network short-terminated and replacing the drain termination with the DC load resistor for power amplifier, the circuit can operate as microwave rectifier with taking part of bandwidth from power amplifier. Measurements show the efficiency bandwidth with larger than 70 % rectifying efficiency at 15 dB input power range over a 1.7–1.95 GHz frequency range. The measurements thereby validate the presented concept and demonstrate the potential of the proposed rectifier for use in future wireless energy harvesting applications.

This paper presents an analysis for the impedance transformation ratio of microwave rectifier, implemented as an energy recycling unit suitable for RF outphasing transmitters. The experimental demonstration is realised by two single-ended microwave rectifiers with different impedance transformation ratios to separately replace the power-wasting resistive load of an isolating combiner in a multilevel LINC system. The measurement results show that the implemented rectifier can improve the overall efficiency of the multilevel LINC system from original 39.5 % to 46.7 % and 44.9 % respectively, without affecting linearity.

This paper proposes a novel implementation of a high frequency rectifier, which is realised using the simplified real frequency technique. The optimum impedances presented at the diode package plane are found from source-pull simulation over a broad frequency range. The implemented broadband rectifiers show good performance in terms of efficiency and bandwidth. Using a HSMS 2820 Schottky diode device, greater than 50 % efficiency has been measured from 1.25 GHz to 2.25 GHz. Furthermore, greater than 60 % efficiency with 14 dB (from 12 dBm to 26 dBm) input power dynamic range is achieved at 1.8 GHz. Peak efficiency of 77 % is obtained at the input power of 23 dBm. The high efficiency over such a large bandwidth is believed to be the best reported to data in open literature at these frequencies.

This paper proposes a novel configuration of the rectifier which is realised using a high impedance inductor. It removes the input matching network concerning the trade-off of the efficiency and bandwidth. The rectifier with better than 40 % efficiency is designed and measured across the frequency band from 40 MHz to 4740 MHz. The peak RF-DC conversion efficiency of 60.3 % is achieved at 1 GHz operating frequency with 23 dBm incident power. In addition, a minimum of 2 V output DC voltage and greater than 40 % efficiency with 5 dB input power dynamic range from 20 dBm to 25 dBm is obtained covering the entire band.

In this paper, the design of a 10 mW concurrent triband RF rectifier at 1050 , 2050 and 2600 MHz using the high impedance transmission line with two short stubs is presented. Experimental results show that the efficiency is achieved 59.2 % at 1050 MHz, 35.6 % at 2050 MHz and 52.2 % at 2600 MHz. Compared to the state-of-the-art of multi-band rectifiers, the proposed triband rectifier has the ability to harvest RF energy from the corresponding operating frequencies sources.

This paper proposes a filter realised using only lumped-element components, implemented as a highly selective bandpass filter suitable for lowpass delta-sigma (LPΔΣ) RF transmitters. The proposed filter is characterised by low insertion loss, high selectivity and a transfer function tailored for filtering the close-up out-of-band noise of LPΔΣ RF transmitters. The circuit design is based on a modified loaded-stub ring-resonator structure, however, implemented using 4 π-shape lumped-element resonators with LC tanks. The measurements show good agreement with simulation and the proposed filter provides a fractional 3-dB bandwidth of 14.3 %, insertion loss of less than 1.6 dB, suppression of more than 18 dB on both sides of the desired band, and a sharp cut-off frequency response. This filter is combined with the delta-sigma transmitter to show the effective reduction of the out-of-band quantisation noise signals.

This paper proposes an energy recovery rectifier suitable for the use in outphasing and/or linear amplification with nonlinear components (LINC) transmitters. The proposed application oriented rectifier consists of a high-efficiency resistive rectifier and a stepped-impedance resonator (SIR) which stores the energy in order to reduce load sensitivity of the circuit. The rectifier is designed including harmonic frequency control to improve conversion efficiency and to provide a resistive input impedance at the fundamental frequency. The proposed rectifier has been implemented in hybrid technology. The fabricated circuit provides peak RF-to-DC efficiency of 73.5 % at 2.3 GHz and more than 60 % over a dynamic range of 8 dB. Furthermore, measurements show good agreement with simulation results.

This paper presents a dual-band rectifying circuit for wireless power transmission working at 2.45 GHz and 5.8 GHz. A modified dual-band matching network is adopted to realize the highly efficient dual-band rectifier. Source-pull simulations are performed, to determine the proper impedances at the two different frequencies. The proposed dual-band rectifier has been implemented and the measurements show good agreement with simulation. With a dual-band input matching network, the measurement results for an input power level of 10 mW show peak RF-to-DC efficiencies of 66.8 % and 51.5 % at 2.45 GHz and 5.8 GHz respectively.

This paper proposes a highly selective bandpass filter suitable for lowpass delta-sigma RF transmitters. The proposed filter is characterized by a low insertion loss, high selectivity and a transfer function tailored for filtering the close-up out-of-band noise of lowpass delta-sigma transmitters. The circuit design is based on a modified stub-loaded ring resonator structure. The proposed filter has been implemented and the measurements show good agreement with simulation. The proposed filter provides a fractional 3-dB bandwidth of 14.6 %, an insertion loss of less than 1.3 dB, a suppression of more than 15 dB on both sides of desired band, and a sharp cut-off frequency response.

This paper presents a high-efficiency rectifying circuit for wireless power transmission at 2.45 GHz. A filtering and matching network designed by quarter wavelength stubs was developed for suppressing the second and the third order harmonics of 2.45 GHz, 4.9 GHz and 7.35 GHz, respectively. The measured RF-to-DC conversion efficiency is 66.5 % for an input power level of 10 mW.