This paper presents a 60 GHz reconfigurable active phase shifter based on a vector modulator implemented in 65 nm complementary metal–oxide–semiconductor technology. This circuit is based on the recombination of two differential paths in quadrature. The proposed vector modulator allows us to generate a phase shift between 0° and 360°. The voltage gain varies between −13 and −9 dB in function of the phase shift generated with a static consumption between 26 and 63 mW depending on its configuration.

This paper presents the development of two dual-band radio-frequency (RF) harvesters optimized to convert far-field RF energy to DC voltage at very low received power. The first one is based on a patch antenna and the second on a dipole antenna. They are both implemented on a standard FR4 substrate with commercially off-the-shelf devices. The two RF harvesters provide a rectified voltage of 1 V for a combined power, respectively, of −19.5 dBm at 915 MHz, −25 dBm at 2.44 GHz, of −20 dBm at 915 MHz, and −15 dBm at 2.44 GHz. The remote powering of a clock consuming 1 V/5 µA is demonstrated, and the rectenna yields a power efficiency of 12%.

This paper presents possible configurations of dual band filters based on transverse magnetic (TM) Dual mode cavities. The concept is to use TM dual-mode cavities in order to design compact dual band filters. High flexibility is obtained in terms of transmission zero (TZ) positioning. By using this approach a number of TZs up to the number of poles is attainable. Zeros can be placed in both the lower and upper stop-bands as well as between the two pass-bands to increase their insulation. The use of TM cavities allows a dramatic reduction of the filter length without significantly reducing the RF performances. Two three-cavity TM dual-band filters with six symmetric and asymmetric TZs have been designed and manufactured to validate the proposed geometry.

The recent developments in electronic cards such as the network equipment are characterized by the miniaturization of the board size and the increasing complexity of the layout. Because of these requirements, multi-layered printed circuit boards are commonly used and vias connecting signal lines on different layers, or integrated circuit devices to power and ground planes, are frequently used and often essential. However, a via is not an ideal transmission line. Besides, it creates discontinuities at high frequencies leading to high insertion loss degradation of signal which limits the performances of integrated circuit and systems. In this paper, the impacts of coupling between via and parallel-plates cavity on the response of microwave integrated devices are highlighted in the first part. Then, to describe the intrinsic interaction between the via transition and parallel-plate modes, the notion of parallel-plates matrix impedances is presented and new boundary conditions like open or plated through holes shielded boundaries of the cavities are introduced. Then, using this physics-based model, an intuitive equivalent circuit has been developed. Finally, the proposed approach and the equivalent circuits were validated by using comparisons with electromagnetic simulations and measurements in different scenarios.

This paper describes a linear-polarized reflector that reflects incident wave almost parallel to its surface at 60 GHz, when illuminated by an impinging plane wave with normal incidence. This structure is designed as a simple and low-cost passive repeater with both a quasi-endfire radiation and a flat profile. Working as a transmission relay, it is a quite potential and possible solution to improve the radio-coverage in the T-shaped corridor, which is a typical scenario of non-light-of-sight (NLOS) environment for 60 GHz indoor communications. The proposed repeater consists of an array of parallel grooves with appropriate depths, drilled in a metallic plate. Full-wave simulations and theoretical investigations are carried out to demonstrate the working principle and to optimize the performance. Then, an 80-groove breadboard in the size of 200 mm × 200 mm is fabricated and measured to explore the feasibility of the concept. In a practical measurement, when the distance from the repeater to transmitting antenna (Tx) is 2 m, and to the receiving antenna (Rx) is 1.5 m, the repeater exhibits a main beam at ±75° with gain up to 22.7 dB. The communication between Tx and Rx in NLOS areas is thus successfully recovered.

This paper reports a differential photoreceiver module designed for short reach applications such as access network and data center interconnect. It consists of a monolithically integrated semi-conductor optical amplifier with a PIN photodiode and a linear transimpedance amplifier (TIA) mounted on the same carrier. A matching circuit is placed between the PIN and the TIA in order to increase the cut-off frequency. The module shows a −3 dB bandwidth of 43 GHz, a single-ended conversion gain of 10 000 V/W for an optical input power of −25 dBm and a sensitivity at 40 Gb/s non-return-to-zero operation of −22.5 dBm for a bit error rate of 10−9.

In this contribution, we study the design and experimental characterization of a reconfigurable transmitarray in X-band with reduced focal distance. To this end, we consider an illumination with four feed horn antennas in two different configurations. The focal distance and the horn configuration in the focal plane have been optimized with an in-house simulation tool. The effects of source placement errors and excitation unbalances are also studied. The numerical results show a reduction of the focal distance by a factor 1.8 if compared with the single-source case, for a reconfigurable 400-element transmitarray designed in X-band. Moreover, generation of multiple beams is considered and demonstrated numerically for spatial power combining applications. The experimental results obtained in radiation are in good agreement with the numerical predictions. This multiple-source transmitarray exhibits similar radiation performances as the single-source one in terms of gain, bandwidth and beam tilting capabilities, but with about half its volume. This technique seems very attractive for a better integration on various platforms such as vehicles, drones, aircrafts, buildings, etc.

In order to evaluate a communication system, we need to model the propagation channel of the relevant environments pertaining to that communication. In this paper, we propose a Geometry-Based Stochastic Channel Modeling approach to build up propagation channel simulations to assess the performance of vehicle-to-vehicle wireless communications. Our methodology allows the simulation of dynamic scenarios, with an electromagnetic simulator, to emulate typical propagation environments (rural, highway and urban-like propagation channels). Simple metallic plates are used to represent scatterers in the simulated geometric configurations. The common characteristics defining a propagation channel such as delay spread, angle of arrival distribution, and the delay-Doppler spectrum are obtained through adjustment of the number and location of those simple metallic plates.

A new split frequency envelope modulator for envelope tracking radio-frequency power amplifiers is proposed based on a lead-lag network. By mathematically deriving the transfer functions of the lead-lag modulator and the conventional split frequency type, the lead-lag is shown to have a significantly flatter phase response. The frequency response of the two modulators is verified by simulation, where the phase transient of the lead-lag is significantly less than the 360° of the conventional type. They are further simulated with a 3 MHz bandwidth 3GPP long-term evolution (LTE) signal and the lead-lag shown to reduce the modulator's normalized root-mean-square error (NRMSE) from −27.3 to −39.2 dB. A practical demonstrator was developed around an existing high-efficiency modulator architecture. To maintain system efficiency synthetic impedance was incorporated in the low-frequency switched mode power supply (SMPS) path. This was achieved with voltage and current feedback around the SMPS. The dynamic wideband signal response was investigated by applying a 3 MHz LTE envelope signal to the modulator and comparing the input and output signals. The measured NRMSE was improved from −27.5 to −30.0 dB by adopting the lead-lag structure and the dynamic frequency response verifies correct operation.

In this study, we propose a design methodology for a switching-mode RF CMOS power amplifier with an output transformer. For a given supply voltage, output power, and target efficiency, the initial values of the transistor size, output inductance, and capacitance can be sequentially determined during the design of the power amplifier. The breakdown voltage of the power transistor is considered in the design methodology. To prove the feasibility of the proposed design methodology, we provide the design example of a 2.4-GHz switching-mode CMOS power amplifier with 180-nm RF CMOS technology. From the measured results, the feasibility of the proposed design methodology is proved.

This paper presents and discusses several methods for predicting the low-frequency (LF) noise at the output of a mm-wave detector. These methods are based on the extraction of LF noise source parameters from the single diode under a specific set of bias conditions and the transfer or conversion of these noise sources, under different operating conditions including cyclostationary regime, to the quasi-dc output of a mm-wave detector constructed with the same model of diode. The noise analysis is based on a conversion-matrix type formulation, which relates the carrier noisy sidebands of the input signal with the detector output spectrum through a pair of transfer functions obtained in commercial software. Measurements of detectors in individual and differential setups will be presented and compared with predictions.

This paper presents the design of a fully integrated ultra-low-power Ultra Wide Band (UWB) pulse generator. The circuit is designed and optimized for low rate and localization applications. This UWB transmitter is based on the impulse response filter method in order to achieve high energy sub-nanosecond pulses. The circuit has been integrated in a ST-Microelectronics CMOS 0.13 μm technology with a supply voltage of 1.2 V on a die area of 0.56 mm2. A power manager is used to reduce the power leakages to 3.91 μW which gives a power consumption of 3.98 Mw at 10 kb/s. The measured dynamic energy consumed per pulse is 68 pJ and the measured energy of the emitted pulse is 2.15 pJ.

This paper presents a full-duplex dual-band orthogonal frequency division duplexing (OFDM) radio architecture that enables the radio transceiver to be more flexible and provides a viable radio link capacity gain. A simple but practical I/Q imbalance estimation and compensation method, based on the frequency-flat-fading behavior of the self-interference channel, is proposed. The performance of the proposed I/Q imbalance compensation method is evaluated by link level simulation conducted with Advanced Design System and Matlab. The co-simulation results show that the proposed radio transceiver could potentially increase the physical layer transmission rate by four times compared with the conventional radio link at the cost of tolerable loss of bit error rate performance. The I/Q imbalance compensation method can effectively compensate both high and low I/Q imbalance without the problem of algorithm convergence.

An efficiency of linear amplification with nonlinear components (LINC) system is degraded due to the low efficiency of a power combiner for high peak-to-average power ratio signals such as long-term evolution signal. A multi-level LINC system can be used to improve the performance of the conventional LINC system. In this paper, a novel 9-point finite difference method to determine the optimal threshold values for 3-level LINC system is suggested. Instead of solving the complicated differential equation, the proposed method can extract optimal threshold values efficiently by numerical method. The 3-level LINC system adopting the proposed scheme and dynamic biasing significantly improves the power efficiency and linear performance simultaneously. The proposed system is verified by comparing the performance of the 3-level system with those of the conventional and 2-level LINC systems.

An efficient platform of wireless power delivery through a pair of coupling coils with a fully integrated complementary metal-oxide-semiconductor (CMOS) rectifier is designed and evaluated in this paper. The research is intended for inductively powered energy harvesting application of biomedical sensor network. By making use of high-performance active diodes fulfilling almost ideal switching (zero forward voltage drop) and circuit to be provided with negative resistance, the proposed rectifier circuit is able to achieve a maximum conversion efficiency of more than 90%. This makes it ultra low-loss without any special device requiring additional manufacturing procedures, thereby featuring dramatically reduced production cost. Experimental studies with respect to all aspects of its performance including that used to emulate a truly biological tissue are given as proof of concept.

In this paper, new planar spiral antennas with meander lines and loads for passive Radiofrequency identification tag application at ultra-high-frequency band are designed and optimized using the global best (gbest)-guided Artificial Bee Colony (GABC) algorithm. The GABC is an improved Artificial Bee Colony algorithm, which includes gbest solution information into the search equation to improve the exploitation. The optimization goals are antenna size minimization, gain maximization, and conjugate matching. The antenna dimensions were optimized and evaluated in conjunction with commercial software FEKO. GABC is compared with other popular algorithms. The optimization results produced show that GABC is a powerful optimization algorithm that can be efficiently applied to tag antenna design problems.

A new flexible and miniaturized power divider (PD), based on the Wilkinson PD topology, is carried out in this paper. Flexibility and size reduction are achieved simultaneously thanks to both an open-stub loading the input port and additional transmission lines (TLines) connecting the output ports to the isolation resistance. Design equations and rules are given. As a proof-of-concept, two PDs working at 2.45 GHz were fabricated and measured. Then, on the basis of the previous developments, a 1:4 power-dividing feeding network was realized. It highlights the high performance and flexibility of the proposed PD. Agreement between simulation and measurement results is very good, for PDs as well as for the feeding network, thus validating the proposed approach. This concept is straightforward to be applied at higher frequencies, in particular in the millimeter-wave range on CMOS technologies, where flexibility in the choice of the TLines characteristic impedances and size reduction are mandatory.

A method allowing for reduction of coupling coefficients required for realization of two-section asymmetrical coupled-line directional couplers has been proposed. It has been shown that by connecting uncoupled left-handed and right-handed transmission lines between two coupled-line sections one can obtain greater design flexibility of the resulting circuit, simultaneously with the coupling reduction in coupled-line sections. Moreover, the proposed circuit features the properties of two-section asymmetric directional couplers offering wide operational bandwidth. The theoretical analysis has been verified by measurements of a 3 dB directional coupler operating at the center frequency f0 = 1.5 GHz having coupling imbalance δC = ±0.4 dB and bandwidth 0.75–2.3 GHz.

The development in high-end microwave transceiver systems toward the software defined radio has brought about the need for tunable frontend filters. Although the problem is being tackled by the microwave community, there still appears to be an unmet demand for practical tunable filter technologies. With this motivation, this work presents a tuning method that delivers a resonator Q0 of 2000–3621 within a minimum tuning ratio of 1:1.42. A continuously tunable notch filter based on this tuning method is presented. The design is manufactured, measured, and verified. It is shown that the tuning technology compares favorably to other selected technologies.