Electroporation has become a powerful technological platform for the electromanipulation of cells and tissues for various medical and biotechnological applications. Recently, nanoporation based on nanosecond pulsed electric fields (nsPEFs) has gained great attention due to its potential to permeabilize the membrane of small vesicles. Here, the authors propose and characterize, both experimentally and through multiphysics modeling, a grounded coplanar waveguide compliant with the wideband requirements for nanosecond pulses to be used for experiments of drug delivery with liposomes activated by nsPEFs.

In this paper, a modular waveguide filter platform suitable for educational and prototyping purposes is presented. The waveguide filter platform is dimensioned to work in the F-band (4.9–7.05 GHz). The design of the platform is discussed and versatile application possibilities are shown in many examples. The platform can be used to realize generalized Chebyshev filters with or without cross-couplings by exploiting TE101 and TE102 mode cavities. Transmission zeros can be introduced by the utilization of wires or aperture couplings. Filter topologies based on the extracted pole technique can be examined as well. Small changes in the set-up also allow the realization of a gap waveguide filter, a diplexer set-up as well as filters with frequency-dependent coupling apertures. Most required components can either be purchased cheaply or be manufactured with a three-dimensional printer.

Realizing packaged state-of-the-art performance of monolithic microwave integrated circuits (MMICs) operating at millimeter wavelengths presents significant challenges in terms of electrical interface circuitry and physical construction. For instance, even with the aid of modern electromagnetic simulation tools, modeling the interaction between the MMIC and its package embedding circuit can lack the necessary precision to achieve optimum device performance. Physical implementation also introduces inaccuracies and requires iterative interface component substitution that can produce variable results, is invasive and risks damaging the MMIC. This paper describes a novel method for in situ optimization of packaged millimeter-wave devices using a pulsed ultraviolet laser to remove pre-selected areas of interface circuit metallization. The method was successfully demonstrated through the optimization of a 183 GHz low noise amplifier destined for use on the MetOp-SG meteorological satellite series. An improvement in amplifier output return loss from an average of 12.9 dB to 22.7 dB was achieved across an operational frequency range of 175–191 GHz and the improved circuit reproduced. We believe that our in situ tuning technique can be applied more widely to planar millimeter-wave interface circuits that are critical in achieving optimum device performance.

Despite the great progress in data transmission systems using dielectric waveguides (DWGs) in the millimeter-wave (mm-wave) frequency band (30–300 GHz), the signal distortions caused by DWGs have not yet been fully understood. However, such investigations would help to optimize DWGs as a transmission channel in order to further increase data rate and transmission distance of such systems without the need for more complex transceivers. Therefore, this paper presents a detailed study of the expected signal distortions caused by frequency-dependent attenuation and frequency-dependent group delay of circular DWGs at mm-wave frequencies. Based on a low-complexity digital transmission system, the effects of DWGs on the signal-to-noise ratio and the intersymbol interference at the receiver are evaluated. The figures and equations given in this paper allow the reader to easily calculate the channel properties and signal distortions for a wide range of circular DWGs without the need of finite element method solver or other time-consuming numerical simulations. Finally, design recommendations are given to minimize signal distortions for transmitting signals along DWGs.

The generation and transmission of millimeter-wave signals for 5G applications require the use of broadband and high output power photodetectors to bridge from the optical and electronic domains. Therefore, the deep knowledge on the equivalent circuit characteristics of these devices is vital. This study reviews and analyzes de-embedding techniques contributing to the characterization of the physical aspects within the active region of uni-traveling carrier photodiodes. De-embedding methods analytically remove the parasitic effects of the electrical transmission lines connected to their active area allowing the extraction of their series resistance and junction capacitance toward the synthesis of an equivalent circuit with lumped elements. The open-short technique is examined and a systematic error introduced by this process underlines the vulnerability of the method on removing parasitics with higher complexity. This error is quantified leading to the implementation of a corrected equation converging with the characteristic features of an $S$-parameter-based de-embedding. These characteristics are also analyzed through simulation approaches showing minimal equivalent inaccuracies on eliminating more complex symmetrical parasitics. A thorough comparison between these three methods is conducted through the calculation of lumped components corresponding to the active region of diodes with different sizes.

New protocols related to Internet-of-things applications may introduce previously unnoticed measurement effects in reverberation chambers (RCs) due to the narrowband nature of these protocols. Such technologies also require less loading to meet the coherence-bandwidth conditions, which may lead to higher variations, hence uncertainties, across the channel. In this work, we extend a previous study of uncertainty in NB-IoT and CAT-M1 device measurements in RCs by providing, for the first time, a comprehensive uncertainty analysis of the components related to the reference and DUT measurements. By use of a significance test, we show that certain components of uncertainty become more dominant for such narrowband protocols, and cannot be considered as negligible, as in current standardized test methods. We show that the uncertainty, if not accounted for by using the extended formulation, will be greatly overestimated and could lead to non-compliance to standards.

This paper presents a fully integrated three-way Doherty architecture to address the challenges of 5G applications using laterally-diffused metal-oxide semiconductor (LDMOS) technology. By using the so-called CDS cancelation method for the Doherty combiner design, a wideband impedance transformation is achieved, that combined with the three-way Doherty power amplifier (DPA) architecture allows for high efficiency in deep back-off, with a reduced load modulation for high bandwidth. Throughout this paper, the design approach and realization are described, while multiple critical design challenges will be addressed such as low frequency drain resonance optimization, impact of in-package coupling effects, and linearity versus efficiency tradeoff. Two state-of-the-art three-way fully integrated LDMOS DPA monolithic microwave integrated circuit (MMICs) are presented to demonstrate how these measures have been successfully applied to different power amplifier (PA) line-up components for 5G base station systems. First, a 60 W 1.8–2.2 GHz multi-stage device for driver application in true dual-band operation is presented. The circuit design pays special attention to extended PA video bandwidth thanks to integrated passive device. After digital pre-distortion (DPD) in dual-band operation, this highly linear device achieves an outstanding adjacent channel leakage ratio (ACLR) of −56 dBc for a 2cLTE 20 MHz 8 dB peak-to-average ratio signal spaced by 345 MHz, thus 385 MHz instantaneous bandwidth (IBW), with 29% efficiency at 35 dBm, 12 dB output back-off (OBO). Second, the simulation and measurement results of a 55 W 2.6 GHz multi-stage DPA for massive-MIMO final stage application are presented, which yields an excellent linearized efficiency of 49% using a 200 MHz 10cLTE signal with an ACLR lower than −47.5 dBc. For 8cLTE 20 MHz (160 MHz IBW), the device yields 50% efficiency with −50.7 dBc ACLR linearized after DPD. The achieved efficiency is well comparable to published GaN DPAs. These results were achieved by improved simulation techniques to minimize frequency dispersion and thus allow high efficiency operation over wide bandwidth. Both devices show that LDMOS is not only a mature technology which allows those PAs to be reliable and low-cost for mass production in very compact packages, but also provide best-in-class RF performance according to the needs of 5G base station systems.

This paper presents the radio frequency (RF) measurements of an SPST switch realized in gallium nitride (GaN)/RF-SOI technology compared to its GaN/silicon (Si) equivalent. The samples are built with an innovative 3D heterogeneous integration technique. The RF switch transistors are GaN-based and the substrate is RF-SOI. The insertion loss obtained is below 0.4 dB up to 30 GHz while being 1 dB lower than its GaN/Si equivalent. This difference comes from the vertical capacitive coupling reduction of the transistor to the substrate. This reduction is estimated to 59% based on a RC network model fitted to S-parameters measurements. In large signal, the linearity study of the substrate through coplanar waveguide transmission line characterization shows the reduction of the average power level of H2 and H3 of 30 dB up to 38 dBm of input power. The large signal characterization of the SPST shows no compression up to 38 dBm and the H2 and H3 rejection levels at 38 dBm are respectively, 68 and 75 dBc.

This study presents an ultra-wideband receiver front-end, designed for a reconfigurable frequency modulated continuous wave radar in a 130 nm SiGe BiCMOS technology. A variety of innovative circuit components and design techniques were employed to achieve the ultra-wide bandwidth, low noise figure (NF), good linearity, and circuit ruggedness to high input power levels. The designed front-end is capable of achieving 1.5–40 GHz bandwidth, 30 dB conversion gain, a double sideband NF of 6–10.7 dB, input return loss better than 7.5 dB and an input referred 1 dB compression point of −23 dBm. The front-end withstands continuous wave power levels of at least 25 and 20 dBm at low band and high band inputs respectively. At 3 V supply voltage, the DC power consumption amounts to 302 mW when the low band is active and 352 mW for the high band case, whereas the total IC size is $3.08\, {\rm nm{^2}}$.

This paper presents the design of a sixth-order cross-coupled L-band filter, specifically intended for space applications. The solution was based on the principle of stepped impedance coaxial resonators (SIRs), which allowed us to fulfill several electrical and size specifications and more particularly a high multipactor threshold. The degrees of freedom afforded by the proposed topology offer a wide choice of design configuration possibilities. Whatever the central frequency and required specifications, several compromises can be made in terms of volume, height, footprint, quality factor, multipactor threshold, harmonic rejection, etc. For instance, SIR coaxial topology is very well suited to small L-band filters when moderate quality factors and multipactor thresholds of around 4000 and 400 W, respectively, are requested. The design procedure is presented and simulations and measurements are compared and discussed.

Bessel, Bessel-Gauss, and Gaussian beams have widely been investigated in optics in the paraxial approximation, under the frame of a scalar wave theory. Such approximations can hardly be applied in the microwave/millimeter-wave range, where the vectorial nature of the electromagnetic fields cannot be neglected, and experimental realizations for some of these beams appeared only recently. In this work, we discuss the generation of Bessel, Bessel-Gauss, and Gaussian beams through a fully vectorial electromagnetic approach. The field derivation of all these beams is first illustrated and numerical evaluations are then reported to compare their different propagation and diffractive behaviors. Finally, an innovative approach for realizing such solutions with planar microwave devices exploiting leaky waves is demonstrated through accurate numerical simulations.

Next-generation automotive radar sensors are increasingly becoming sensitive to cost and size, which will leverage monolithically integrated radar system-on-Chips (SoC). This article discusses the challenges and the opportunities of the integration of the millimeter-wave frontend along with the digital backend. A 76–81 GHz radar SoC is presented as an evaluation vehicle for an automotive, fully depleted silicon-over-insulator 22 nm CMOS technology. It features a digitally controlled oscillator, 2-millimeter-wave transmit channels and receive channels, an analog base-band with analog-to-digital conversion as well as a digital signal processing unit with on-chip memory. The radar SoC evaluation chip is packaged and flip-chip mounted to a high frequency printed circuit board for functional demonstration and performance evaluation.

Millimeter-wave band-pass filters using spherical dielectric resonators are presented. The dielectric spheres are sandwiched between metal plates and are excited by a simple microstrip line structure on a thin-film circuit board. As such, these filters could also be implemented in the back-end-of-line layers of an integrated circuit. A single resonator, based on a diameter 0.6 mm alumina ceramic sphere, is shown to resonate with high unloaded Q-factor of 750 at 170 GHz. A three-sphere band-pass filter is measured showing <5 dB insertion loss and 0.4% bandwidth at 170 GHz. A concept for mechanically tuning of a two-sphere band-pass filter is demonstrated for a filter operating around 105 GHz. The measured filter shows approximately 5 dB insertion loss and <0.5% bandwidth and its passband can be varied over 3 GHz of frequency, or 3%. Technological challenges are discussed.

One of the current trends in the integrated circuit (IC) development is the integration of antennas on-chip or in the package of the IC. This poses challenges in the production testing process of the packaged IC, as the antenna functionality has to be included and at least one of the signal ports cannot be accessed at a conducted manner. In order to measure the reflection coefficient of an integrated antenna, a contactless characterization method (CCM) can be used. In this paper, the practicality of a CCM is assessed, having the application of a cost-effective high-volume testing procedure for integrated antennas in mind. It is shown that the CCM yields accurate results for different imperfections in the measurement setup. Moreover, measurement results around 33 GHz using a connectorized patch antenna are shown, which experimentally verify the validity of using the CCM under near-field conditions.

In this paper, a compact quintuple notched-band ultra-wideband bandpass filter with high selectivity and wide bandwidth is proposed. The filter adopts an approximate closed-loop C-shaped stepped impedance resonator to generate triple notched bands, and uses Hilbert fractal curve slit and L-shaped resonator to create single notched band, respectively. Multiple notched-band are centered at 5.29, 6.61, 7.92, 8.95, and 9.93 GHz to eliminate undesired interference from coexisting wireless services of WLAN, C-band, and X-band. Additionally, two transmission zeros are introduced to enhance the sharp skirt selectivity up to 0.944. This filter could exhibit high sharp selectivity and wider bandwidth simultaneously. The filter is fabricated on a RT/Duroid 5880 substrate (ɛr = 2.2 and thickness = 0.787 mm) and measured to verify the simulation results. Both simulation and measurement are in well agreement, showing the good performance of the filter.

Each of the various methods for mixed-mode load-pull measurements, which can be found in literature, has its own advantages and disadvantages. In this publication, we analyze two of the most commonly used setups and a third setup of which we provided an initial treatment in a previous publication. We investigated the impact of 180° hybrids on the tuning capabilities of a mixed-mode load-pull system. Furthermore, we provide a rule-of-thumb to easily estimate this impact using only some specifications of hybrids. For all analyzed setups, we use measurement results to show that the tuning range of the newly proposed setup is superior compared to the other setups, though hardware effort and tuning complexity are greater.

In this paper, different techniques for the generation of additional transmission zeros (TZs) in planar waveguide filters are investigated. In the classical theory, TZs are generated only by destructive interference of non-adjacent cavities, limiting the available number of TZs to the filter order itself. However, more approaches for the generation of TZs are known, including bypass-coupling in oversized cavities, frequency-dependent coupling apertures as well as dispersive/resonant TZs which can be realized by the direct source to load cross-coupling. The aim of this paper is to combine several of the strategies in one physical filter set-up to increase the maximal number of TZs beyond the filter order. Different Ku-band fourth-order filter set-ups are presented, showing in total between six and eight real as well as complex TZs. Three filters are manufactured as a proof of concept and compared with the simulation, showing very good agreement.

The plane wave diffraction by a planar junction consisting of a thick metallic sheet and a lossy double-negative metamaterial slab is studied by using the Uniform Asymptotic Physical Optics approach. This approach assumes the radiation integral as a starting point and uses the physical optics surface currents as sources to be integrated. The integral is manipulated by taking advantage of useful approximations and evaluations, and re-formulated in order to apply an asymptotic procedure able to generate a closed-form approximate solution in the framework of the Uniform Geometrical Theory of Diffraction. Accordingly, advantages and drawbacks result from the application of the proposed solution. The jumps of the geometrical optics field are compensated. Implementation and handling of the computer code are facilitated by the evaluation of well-known functions and parameters. No differential/integral equations or special functions must be computed.

Accurate near-field measurements for either deterministic or stochastic electromagnetic fields characterization require a relevant process that removes the influence of the probes, transmission lines, and measurement circuits. The main part of the experimental work presented here is related to a calibration procedure of a test setup consisting of a microstrip test structure and a scanning loop probe. The calibration characteristic, obtained by comparing measured and simulated results, is then used to convert the measured voltage into the magnetic field across and along the microstrip line at the specific height above it. By performing the measurements and simulations of the same test structure with the loop probe in the presence of an additional scanning probe, the influence of the additional probe to the measured output is thoroughly investigated and relevant corrections are given. These corrections can be important when two-point correlation measurement is required, especially in scanning points when two probes are mutually close.