Future Deep Space (DS) ground stations envisioned by running projects funded by major space agencies are based on arrays of reflector antennas operating in different frequency bands. Therefore, a multi-band feeding system is required for each antenna, and a possible solution foresees the use of dichroic mirrors to separate/combine different beams. This paper presents a low-cost and fast manufacturing process for the fabrication of dichroic mirrors, usually referred to as punching technique or metal stamping. In particular, the specific advantages and limits of this fabrication technique are outlined and discussed, showing both electrical performance and manufacturing accuracy measurements from a test prototype. In addition, a typical scenario for future DS ground stations is described, showing the impact of these low-cost dichroic mirrors on the final ground station performance and cost, compared to the standard approach for dichroic mirror manufacturing based on more expensive and time-consuming technologies (e.g. milling machining).

This paper introduces a new approach to the modeling of capacitance in field-effect transistor (FET) devices, which we call division by current. It is compared with existing formulations, which we call division by capacitance and division by charge. In doing so, it is necessary to normalize the theory of nonlinear capacitances and to clarify a number of matters. These include charge conservation and determination of charge functions from capacitance measurements, which are often misstated in the literature. We find the division by current formulation to be practical and to have significant advantages in the generation of FET models and in circuit simulation.

Many scientists and engineers contributed – more or less successfully – to the development of radio and wireless. This historical survey describes briefly the projects realized more than a century ago by some of them, at the early beginnings of wireless. It is hoped, in this manner, to draw attention to the unknown or forgotten researchers who built up the considerable body of knowledge that led to Marconi's remarkable achievements.

A broadband Monolithic Microwave Integrated Circuit (MMIC) amplifier, with 12 ± 2 dB gain across the 0.1–27 GHz band has been demonstrated using the AlGaN/GaN on SiC technology. The amplifier design employs a non-conventional, series-DC/RF-High Electron Mobility Transistor (HEMT) configuration. This configuration provides an alternative design to the conventional traveling-wave amplifier (TWA). It results in a smaller MMIC chip size, and extends amplifier gain to the low-frequency region. The amplifier MMIC utilizes four HEMT devices in series and could be biased at voltages up to 120 V.

This paper describes a compact and efficient rectenna based on a dual-diode microstrip rectifier at 2.45 GHz. This circuit has been designed and optimized using a global analysis technique which associates electromagnetic and circuit approaches. Due to the differential topology of the rectifier, neither input low-pass filter nor via-hole connections are needed. This makes the structure more compact reducing losses. Measurements of a single rectenna element show 83% efficiency over an optimal load of 1050 Ω at a power density of 0.31 mW/cm2. To increase the received RF power and then increase dc power over the load, identical rectennas have been interconnected to form arrays. Two and four elements rectenna arrays, connected either in parallel or in series, have been developed. It was shown that by properly choosing the interconnection topology and the optimal output load, higher dc voltage or dc power have been obtained. The four-element series-connected array can provide experimentally up to 3.85 times output dc voltage compared to the single rectenna. The parallel-connected rectenna arrays generate approximately 2.15 and 3.75 times output dc power for two and four elements, respectively.

We discuss the impact of orbital fluctuations on the noise spectrum of a free-running oscillator, exploiting a rigorous nonlinear perturbative analysis based on the Floquet theory, and providing evidence of its relevance for high-Q oscillators.

Multi-satellite missions, such as the next generation of METEOSAT geostationary satellites, require a ground station able to support an arbitrary number of satellites that can fly wherever within a pre-determined sky region, called control box. The use of high frequencies, around 26 GHz, imposes on the ground station high antenna gains to compensate for the noise temperature collected at those frequencies to obtain the specified G/T. Regardless of the narrow beamwidths that emerged from the adoption of high antenna gains, it is also required to operate with fixed (i.e. without any kind of tracking) antennas. This paper shows how all these specifications drive a new type of ground station with respect to current solutions. The proposed architecture is based on a multi-reflector system able to provide a set of interleaved beams, which generates an almost uniform coverage of the control box. The architecture is analyzed and designed, optimizing all the main antenna parameters, and presenting the analytical results.

This paper gives an overview of the low-complexity radio frequency microelectromechanical systems (RF MEMS) switch concept and technology of EADS Innovation Works in Germany. Starting in 2003, a capacitive switch concept, which is unique in several aspects, was developed to address specific needs in the aeronautic and space. Thermally grown silicon oxide as dielectric layer, the silicon substrate as actuation electrode, and a conductive zone realized by ion implantation make the EADS RF MEMS switch a very simple, low-cost, and reliable approach. In this document, data on experimental investigations are presented, which demonstrate outstanding performance figures in terms of insertion loss, isolation, frequency range, bandwidth, RF-power handling, and robustness with respect to thermal load. Based on this concept, numerous different circuits in particular single-pole single-throws (SPSTs), single-pole multi-throws (SPMTs), tunable filters, phase shifters, and electronically steerable antennas between 6 and 100 GHz have been designed, fabricated, and characterized.

This paper gives an overview of frequency regulation, standardization, and applications of 60 GHz communication systems. Based on forecasted developments of mobile IP traffic, the motivation for investigating circuits, and systems for the 60 GHz band is underlined. Some physical properties of 60 GHz radio waves are outlined and implications on potential applications are sketched. The current international and European frequency regulation aspects are presented. The main parameters of three different international standards are summarized and compared with each other. Details of channel spacing and channel bonding are given. Based on the investigation of different applications, the main system requirements are derived. Finally, some information on protocol issues and system integration aspects are given.

This paper reports on the potential of RF-MEMS technology based on aluminum nitride capacitive dielectric and nickel-suspended membranes to provide RF circuit functions in reconfigurable front-end radios. The RF performance of capacitive switches, distributed MEMS transmission lines (DMTLs) phase shifters for beam steering and tunable filters, including center frequency and bandwidth tuning of bandpass and band-stop filters are presented. Detailed characterization based on S-parameter data demonstrates very promising figures of merit of all fabricated demonstrators from 5 to 40 GHz.

This paper describes the design of a 12-monopole linear array to perform a radiation pattern in the array alignment plane. This antenna can be used for HyperLAN2 telecommunications in transit vehicles. The design is based on a rigorous method which synthesizes the feeds weights by considering the strong cumulative coupling between monopoles. The originality of this paper consists in considering the couplings to obtain the objective pattern. Without this approach, a significant performance alteration is observed. The array and the feed network have been designed and successfully measured.

This paper reports the test results of a small-scale prototype that implements a digitally beam-formed phased antenna array in the E-band. A four-channel dual-conversion receive RF module for 71–76 GHz frequency band has been developed and integrated with a linear end-fire antenna array. Wideband frequency-domain angle-of-arrival estimation and beam-forming algorithms were developed and implemented using Orthogonal Frequency Division Multiplexing (OFDM) with Quadrature Phase-Shift Keying (QPSK) at 1 Gbps. Measured performance is very close to the simulated results and experimental data for an analogue-beam-formed array. This work is a stepping stone toward practical realization of larger hybrid arrays in the E-band.

An analysis of operation of a modified inverse class E power amplifier is presented. The proposed amplifier that has a series tunable parallel resonant tank is similar to a hybrid of class F and inverse class E. The principles and design equations required to determine the optimum operation of the amplifier are analyzed in detail. The practical circuit using LDMOS MRF21010 is shown to be able to deliver 40.02 dBm outpout power at 155 MHz. The amplifier achieves power-added efficiency (PAE) of 78.18% and drain efficiency of 78.42%, and exhibits 25.02 dB power gain when operates from a 21 V supply voltage. Comparisons of simulated and measured results are given with good agreement between them being achieved.

In this work a de-embedding technique oriented to the evaluation of the load line at the intrinsic resistive core of microwave FET devices is presented. The approach combines vector high-frequency nonlinear load-pull measurements with an accurate description of the reactive nonlinearities, thus allowing one to determine the actual load line of the drain–source current generator under realistic conditions. Thanks to the proposed approach, the dispersive behavior of the resistive core and the compatibility of the voltage and current waveforms with reliability requirements can be directly monitored. Different experiments carried out on a gallium nitride HEMT sample are reported.

A 52–61 GHz power amplifier (PA) is implemented in 65 nm bulk complementary metal oxide semiconductor (CMOS) technology. The proposed PA employs a transformer-based power combiner to sum the output power from two unit PAs. Each unit PA uses transformer-coupled two-stage differential cascode topology. The differential cascode PA is able to increase the output power and ensure stability. The transformer-based passives enable a compact layout with the PA core area of only 0.3 mm2. The PA achieves a peak power gain of 10.2 dB with 3-dB bandwidth of 9 GHz. The measured saturated output power is 14.8 dBm with a peak power-added efficiency (PAE) of 7.2%. The reverse isolation is smaller than −33 dB from 25 to 65 GHz. The PA consumes a quiescent current of 143 mA from a 1.6 V supply.

In this paper, a method for design and optimization of folded reflect-array antennas is proposed based on particleswarm optimization (PSO). In addition to such a powerful optimization algorithm, two further requirements have to be fulfilled. The first one is a good and fast algorithm for the exact prognosis of the far-field radiation diagram, resulting from a specific element configuration on the reflector. Additionally, a good choice of the fitness function for the evaluation of the resulting radiation diagrams is necessary. In both, reflect-array-related aspects such as phase truncation, reflection losses, and cell discontinuities have to be considered. Antenna optimization based on this technique is presented in this paper at the example of two 77 GHz folded reflect-array antennas. The efficiency of this approach is demonstrated with these examples, and the results are verified by measurement, showing an excellent agreement with the specifications of the diagram masks. The implemented tool, including a realistic antenna diagram preview, allows the investigation of the design parameters’ influence on the antenna performance, such as illumination amplitude, high substrate losses, and phase truncation.

A nonlinear circuit model (NCM) with physical parameters is proposed for direct simulation of the RF characteristics of GaN high-electron-mobility transistors (GaN HEMTs) on the basis of device structure. The physical equations are used for the construction of the model in order to connect strongly the model parameters with the device/physical parameters. Hyperbolic tangent functions are used as the model equations to ensure good model convergence and rapid simulation (short simulation time). The usefulness of these equations is confirmed by technology computer aided design (TCAD) simulation. The number of model parameters for the nonlinear components (Ids, Cgs, Cgd) is reduced to 17 by using common physical parameters for modeling the drain current and capacitance. The accuracy of this model is verified by applying to GaN HEMTs. The modeled I–V and capacitance characteristics agree well with the measurement data over a wide voltage range. Furthermore, this model can be used for the accurate evaluation of S-parameters and large-signal RF characteristics.