The present paper presents a fully differential 60 GHz four stages low-noise amplifier for wireless applications. The amplifier has been optimized for low-noise, high-gain, and low-power consumption, and implemented in a 90 nm low-power CMOS technology. Matching and common-mode rejection networks have been realized using shielded coplanar transmission lines. The amplifier achieves a peak small-signal gain of 21.3 dB and an average noise figure of 5.4 dB along with power consumption of 30 mW and occupying only 0.38 mm2 pads included. The detailed design procedure and the achieved measurement results are presented in this work.

This paper presents the design methodology and the realization of a highly linear and power-efficient reconfigurable dual-band amplifier based on the continuous/Class-ABJ approach. The Class-ABJ theory allows presenting different reactive solutions on both fundamental and second harmonic terminations compared with the standard Class-AB mode. Despite the various terminations, a constant optimum output performance in terms of power, gain, and efficiency can still be achieved. The output impedances are then translated into frequency thus allowing the realization of broadband power amplifiers (PAs) at high-power level of 30 W. In this work, the Class-ABJ broadband approach will be used for the realization of a reconfigurable dual-band power amplifier operating in the two frequency bands 2.1–2.2 and 2.5–2.6 GHz. Continuous wave (CW) measurements on the realized PA show power and efficiency greater than 17 W and 55% in the two frequency bands with peak values up to 30 W and 63.7%. Indeed, it is shown that such novel modes can be predistorted and therefore the linearity requirement can also be met.

We present a technique allowing the stabilization and tuning of a modulation sideband in the presence of high-carrier frequency jitter and increased carrier phase noise. This technique is of particular interest in communication systems where oscillators providing the carrier signal cannot be stabilized by a conventional phase-locked loop, such as systems relying on low-cost optical LO generation techniques. The results obtained in simulation are validated by measurements carried out on a modular system demonstrator.

Directional modulation (DM) is a recently introduced technique for secure wireless transmission using direct physical layer wave-front manipulation. This paper provides a bit error rate (BER)-based DM array synthesis method. It is shown for the first time that the standard constellation mappings in In-phase and Quadrature (IQ) space to a pre-specified BER can be exactly achieved along a given specified spatial direction. Different receiver capabilities are investigated and different assessment metrics for each case are discussed. The approach is validated for a 1 × 4 element dipole array operating at 1 GHz.

Ultra-compact band-pass filters with Nth-order pseudoelliptic response are presented allowing dramatic volume and mass savings (up to about 90%) compared to conventional filters at the price of a modest Q-factor reduction. TM dual-mode cavities loaded with high-permittivity (εr > 30) ceramic cylinders are employed, while non-resonating modes are used to create N transmission zeros symmetrically or non-symmetrically located in the pass-band. A single cavity behaves as a generalized doublet generating two transmission poles and two transmission zeros and is used as a basic building block for N-pole and N-zero filters with symmetric or asymmetric response. To prove the effectiveness of the approach, a very compact fourth-order filter with 4.35 GHz center frequency, four transmission zeros has been designed, fabricated, and tested showing an unloaded Q close to 2000. It is finally shown that the filter response can be shifted in frequency by simply replacing the dielectric material with another having different εr, so that the same metal enclosure can be used to realize various filters operating at different frequency bands.

This paper presents a band-notched ultra-wideband bandpass filter by loading a short stub and an asymmetric step impedance stub in a uniform impedance resonator. The passband extends from 3.04 to 10.8 GHz frequency. The multimode resonator provides a sharp band edge with measured transmission zeros at 2.59 and 13 GHz. The later one is due to source load coupling. The passband insertion loss is within 1.5 dB. The embedded spiral resonator introduces a notch at 5.25 GHz with attenuation of 15 dB. The filter exhibits a wide stop band till 15 GHz. The in band and out of band performance obtained from full-wave electromagnetic simulation and measurement are in close agreement.

A novel coplanar waveguide fed Industrial, Scientific, and Medical (ISM) band implantable crossed-type triangular slot antenna is proposed for biomedical applications. The antenna operates at the center frequency of 2450 MHz, which is in ISM band, to support GHz wideband communication for high-data rate implantable biomedical application. The size of the antenna is 78 mm3 (10 mm × 12 mm × 0.65 mm). The simulated and measured bandwidths are 7.9 and 8.2% at the resonant frequency of 2.45 GHz. The specific absorption rate distribution induced by the implantable antenna inside a human body tissue model is evaluated. The communication between the implanted antenna and external device is also examined. The proposed antenna has substantial merits such as miniaturization, lower return loss, better impedance matching, and high gain over other implanted antennas.

A design of low mutual coupling between two microstrip patch antennas for multi input multi output antenna is presented. The two antenna elements operate at 5.8 GHz for wireless applications. The reduction of mutual coupling between the antenna elements is achieved by using a defected ground structure (DGS). The DGS is inserted between the microstrip patch antenna elements to limit the surface waves between them. The separation between the edges of the two elements has been achieved to be only 0.058λ0. The analysis of the correlation coefficient, diversity gain and total active reflection coefficient is presented to validate the performance of the multiple-input–multiple-output (MIMO) antenna. The isolation of the proposed MIMO antenna is 28 dB at 5.8 GHz and the envelope correlation equals 0.003. Owing to these good performances each antenna can operate almost independently. A good agreement is achieved between the simulated and the measured results.

In this paper, an optimized hyper beamforming method is presented based on a hyper beam exponent parameter for receiving linear antenna arrays using a new meta-heuristic search method based on the Firefly algorithm (FFA). A hyper beam is derived from the sum and difference beam patterns of the array, each raised to the power of a hyper beam exponent parameter. As compared to the conventional hyper beamforming of the linear antenna array, FFA applied to the hyper beam of the same array can achieve much more reduction in sidelobe level (SLL) and improved first null beam width (FNBW), keeping the same value of the hyper beam exponent. As compared to the uniformly excited linear antenna array with inter-element spacing of λ/2, conventional non-optimized hyper beamforming and optimal hyper beamforming of the same obtained by real-coded genetic algorithm, particle swarm optimization and Differential evolution, FFA applied to the hyper beam of the same array can achieve much greater reduction in SLL and same or less FNBW, keeping the same value of the hyper beam exponent parameter. The whole experiment has been performed for 10-, 14-, and 20-element linear antenna arrays.

This paper presents a circuit architecture for a new integrated on chip test method for microwave circuits. The proposed built-in-self-test (BIST) cell targets a direct low-cost measurement technique of the gain and the 1 dB input compression point (CP1) of a K-band satellite receiver in the 18–22 GHz frequency bandwidth. A signal generator at the radiofrequency (RF) front end input of the device under test (DUT) has been integrated on the same chip. To inject this RF signal, a loopback technique has been used and the design has been accommodated for it. This paper focuses on the design of the most sensitive block of the BIST circuit, i.e. the RF signal generator. This circuit, fabricated in a SIGe:C BiCMOS process, consumes 10 mA. It presents a dynamic power range of 17 dB (−41; −24 dBm) and operates in a frequency range of 5.6 GHz (17.5; 23 GHz). This BIST circuit gives new perspectives in terms of test strategy, cost reduction, and measurement accuracy for microwave-integrated circuits and could be adapted for mm-wave circuits.

In this paper, the design methodology of a flat reflector composed with standard dielectric material and using transformation electromagnetics (TE) is presented. First, the mathematical relation between a flat reflector and a parabolic one is described. The TE principle is then described. Some realization issues are highlighted, leading to approximations and compromises in order to design a more realistic structure. In this way, a flat reflector made only with standard dielectric materials is presented, using an original method to achieve the desired spatial permittivity variation. The simulation results of different configurations for the flat reflector are presented and compared to classical solutions in order to prove the thickness reduction and the improvement of radiation characteristics in terms of gain and half-power beamwidth.

This paper presents a simulation approach of optical heterodyne systems by using the equivalent circuit representation of a distributed feedback laser (DFB) in the electrical domain. Since the electrical representation of the DFB laser is developed from the rate equations, its characteristics such as non-linearity, relative intensity noise (RIN), and phase noise can be predicted precisely for various biasing conditions. The model is integrated in a heterodyne radio over fiber (RoF) system where two DFB lasers are used to generate a millimeter-wave (mm-wave) signal. An optical phase-locked loop is also introduced to reduce the phase noise on the mm-wave signal. The optical phase noise contribution of individual lasers to the mm-wave signal is evaluated and compared with theoretical results. It is shown that the phase noise of the mm-wave is reduced considerably depending on the loop bandwidth and propagation delay. With the circuit simulation approach proposed, optical and mm-wave phase noises can be studied together with other circuit environments such as parasitic effects and driver circuits.