The progressions in the field of wireless technology can be highly attributed to the development of antennas, which can access high data rates, provide significant gain and uniform radiation characteristics. One such antenna called the Vivaldi antenna has attracted the utmost attention of the researchers owing to its high gain, wide bandwidth, low cross-polarization, and stable radiation characteristics

A compact antenna module with a single band notch at wireless local area network (WLAN) (5.725–5.825 GHz) for ultra-wideband (UWB) multiple input multiple output (MIMO) applications is proposed. Proposed antenna which acquires size of 0.299 λ × 0.413 λ × 0.005 λ mm3 at 3.1 GHz consists of two symmetrical radiators placed side by side on global merchandise link (GML) 1000 substrate (εr = 3.2, tan δ

The paper presents a 1 × 2 B-shaped antenna array for dual-band operation at 4 and 8 GHz. The antenna design consists of a rectangular patch with two annular-strip lines fabricated on the top layer and finite ground plane on the bottom layer. The array is formed by designing an optimum T-shaped microstrip line for impedance matching. The dimensions of the antenna array are 78 × 36 × 1.6 mm3. Full-wave

In this study, the problem of backward heating in microwave ablation technique is examined and an electromagnetic solution based on the use of high impedance graphene material is presented for its mitigation. In this context, a one-atom-thick graphene layer is added on the coaxial double slot antenna. In addition to the electromagnetic behavior, thermal effects caused by the graphene-covered antenna

In this paper, a novel SIW microwave sensor is designed to accurately determine the broadband complex permittivity of medium loss and dispersive liquids using a number of higher order modes in 11–20 GHz. To achieve a higher accuracy in characterization, the sensor is equipped with some methods such as Photonic Band Gap method, slow-wave via, and a new feedline, which enhances the quality factor for

Proposed is a wideband, low profile, fully flexible, and all-textile-based slotted triangular antenna loaded with a 2 × 2 textile-inspired artificial magnetic conductor to be worn on the wrist. The integrated antenna design is designed to cover the frequency band from 3.1 to 6.5 GHz. The integrated design has two main resonances, where the first one is at 3.5 GHz, which can serve the WiMAX communication

A novel, broadband, nonlinear behavioral model, based on support vector regression (SVR) is presented in this paper. The proposed model, distinct from existing SVR-based models, incorporates frequency information into its formalism, allowing the model to perform accurate prediction across a wide frequency band. The basic theory of the proposed model, along with model implementation and the model extraction

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

A miniaturized high-isolation quadplexer with wide upper-stopband based on open and short stub-loaded multimode-resonator is proposed in this paper. Based on the theory of multimode-resonator and stepped impedance resonator (SIR), the compact quadplexer is designed by using multimode-resonator and SIR. In order to further miniaturize the size of the circuit, the multimode resonator is employed as the

In this paper, dual-band and tri-band bandpass filters (BPFs) with fully independent and controllable passbands based on multipath-embedded resonators are presented. The dual-band BPF consists of two double open-ended stub-loaded terminal-shorted resonators (DOESL-TSRs) with a common via-hole connected along the symmetric plane of the filter. Based on DOESL-TSRs, a triple open-ended stub-loaded terminal-shorted

This paper presents a low-profile multi-slotted patch antenna for long term evolution (LTE) and fifth-generation (5G) communication applications. The studied antenna comprised of a stepped patch and a ground plane. To attain the required operating band, three slots have been inserted within the patch. The insertion of the slots enhances the capacitive effect and helps the prototype antenna to achieve

In this paper, a miniaturized tri-band bandpass microstrip filter using stub loaded rectangular ring resonator (SLRRR)，shorted stub loaded stepped impedance resonators (SSLSIR), and stepped impedance resonators (SIR) with sharp skirts is presented. Two SSLSIRs are embedded paralleled inside SLRRR to generate a quasi-elliptic response at second and third passband. The odd-even fundamental resonant mode

We propose simple designs of compact patch antennas with bandwidth enhancement. Firstly, an inverted “L” strip is loaded onto the corner of one radiating patch edge to create an additional resonant mode which can be combined with that one of the conventional patch to enhance the operating bandwidth. Secondly, the “L” strip is replaced by inverted “T” strip to improve further the bandwidth by creating

In this paper, a super-compact ultra-wideband (UWB) metamaterial absorber (MMA) is presented. The absorber design consists of an inverted L-shaped structure and a diagonal rectangular-shaped structure. The capacitive coupling between these two structures not only provides UWB nature but also provides a super-compact absorber design. The dimension of the unit cell arrangement is 5 × 5 mm2 and printed

A planar rectangular slot antenna with dual-band operation and realized higher peak gain is proposed, designed, and fabricated for sub-6 GHz 5G applications. The antenna possesses a rectangular radiating slot with the inverted stub on its upper edge excited simultaneously by a micro-strip feed line having a double folded T-shaped structure. The fabricated design is of compact size with the radiating

A compact antipodal Vivaldi antenna with superwideband characteristics is presented in this paper. For improved matching of input impedance at lower frequency region, techniques like binomial tapering of outer edges, binomial slit loaded outer edge, and protruded binomial tapered stub loading have been adopted. The antenna operates in a wide frequency range from 2 to 20 GHz. Experimental results show

This paper presents the design of frequency-tunable dual-band, tri-band and quad-band bandpass filters (BPFs). The proposed three BPFs can be independently tuned and individually switched by varying the capacitances of the varactors. In the designed tunable dual-band BPF (TD-BPF), common input/output feed lines are utilized for two tunable dual-mode resonators (TDRs). Further, three TDRs and four TDRs

Sigma-delta radio over fiber (ΣΔ-RoF) is an expedient technology for next-generation networks including 5G cloud/centralized radio access networks (C-RAN). In this article, we demonstrate a realistic experimental scenario for ΣΔ-RoF link targeting C-RAN fronthaul applications, by using baseband second-order 1-bit sigma-delta modulation (ΣΔ-M). The experimental set-up validates the LTE 20 MHz signals

This paper proposes and presents a millimeter-wave (MMW) fundamental and subharmonic hybrid mixer in a 65-nm CMOS technology. Based on a hybrid structure with two switching quads and a quasi-diplexer, the proposed circuit can function either as a fundamental mixer (FM) or a subharmonic mixer (SHM) for dual-band applications. An application of the MMW hybrid mixer in a concurrent dual-band receiver

This paper presents a rollable metamaterial screen for high-efficiency wireless power transfer (WPT) system based on magnetic resonance coupling, which operates at 4.5 MHz. The rollable metamaterial screen with a fully expanded area of 750 mm × 750 mm is located in the middle between transmitter and receiver coils and focuses the magnetic field and, by such a way, significantly improves power transfer

High-order sub-harmonically injection-locked oscillators have recently been proposed for low phase-noise frequency generation, with carrier-selection capabilities. Though excellent experimental behavior has been demonstrated, the analysis/simulation of these circuits is demanding, due to the high ratio between the oscillation frequency and the frequency of the input source. This work provides an analysis

This paper presents a high-efficiency linear GaN K-band transmitter for broadband high peak-average power ratio (PAPR) signals. A GaN MMIC 18.5–24 GHz three-stage power amplifier with over 4 W peak output power, 20 dB saturated gain, and 40% peak PAE is supply-modulated with a four-level discrete dynamic supply GaN MMIC. For 100 MHz signals with ${\rm PAPR}\gt 10\, {\rm dB}$ , we demonstrate an average

In this paper, an orthogonal frequency-division multiplexing (OFDM) waveform radar sensing approach is demonstrated based on field measurements at C-band. We demonstrate a concept that is based on the exploitation of typical wireless communication transmissions to perform passive, distributed radar sensing. Our concept is based on an OFDM radar that operates in the modulation symbol domain and can

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

A miniature dual-band bandpass filter with interlocked stepped-impedance resonators (SIRs) is presented in this paper, which was designed for the student design competition held in European Microwave Week 2019. This bandpass filter is required to have two concurrent passbands, namely, the first passband at 900–1000 MHz and the second passband at 1427–1518 MHz bands, which cover six designated bands

A compact co-planar waveguide (CPW) fed planar elliptical antenna has been designed and presented for super wideband (SWB) characteristics. The designed antenna has an overall size of 30 × 30 × 1.57 mm3, and it consists of an elliptical patch radiator fed using a modified 50 Ω CPW-fed tapered microstrip feed line. By using a semi-ring shaped structure with a tapered feed line, an impedance bandwidth

Multi-device radio frequency power amplifiers (PAs) often exhibit strongly non-linear behavior in combination with long-term memory effects, leading to an extremely challenging model development cycle. This paper presents a new, dynamic, behavioral modeling technique, based on a combination of the real-valued decomposed piecewise method and concepts from the field of machine learning. The underlying

Design of single-feed circularly polarized (CP) microstrip antenna is proposed in this article. The design employs the concept of E-shape patch with inclined fractal defected ground structure (IFDGS), which can improve the impedance bandwidth, gain, and axial ratio (AR) bandwidth. The excellent enhanced impedance bandwidth, axial ratio bandwidth, and gain are achieved by an inclined E-shaped fractal

A mode converter design using the concept of periodic substrates loading in a circular waveguide, to convert TM01 mode to TE11 mode is presented in this paper. The detailed design principle, simulation, and measurement results are included in this study. Simulation results show that the purity of output fundamental TE11 mode of the converter approaches 99.2% for an operating frequency of 3.2 GHz. The

This paper presents a 31 GHz integrated power amplifier (PA) in 28 nm Fully Depleted Silicon-On-Insulator Complementary Metal Oxide Semiconductor (FD-SOI CMOS) technology and targeting SoC implementation for 5 G applications. Fine-grain wide range power control with more than 10 dB tuning range is enabled by body biasing feature while the design improves voltage standing wave ratio (VSWR) robustness

In this paper, the antenna reconfigurable technology is used to redesign a whip antenna in different sub-bands of high frequency (HF). According to the electrical characteristics of the antenna, on the one hand, two different radiation whip heights are designed to solve the problem of pattern up-warping in the high-frequency band; on the other hand, a common upper loading network and several different

In this paper, a new printed triple-band planar antenna combing two different modified monopoles and an arc-shaped defected ground plane is proposed and studied. The used two simple monopoles consist of a rectangular ring and a rectangular patch attached a straight metal strip. And a compact arc-shaped defected ground structure is proposed and used to excite higher resonance frequency and improve the

In this paper, a high selectivity wideband 180° phase shifter (PS) with the functionality of vertical transition is presented. The whole circuit is realized based on the hybrid microstrip/slotline (SL) structure. By introducing the short-circuited microstrip stepped-impedance resonators, two transmission zeros are created to improve the selectivity of the PS. With the SL in the center ground layer

In this paper, a simple and efficient method to increase the gain and bandwidth of the wearable antennas used in several medical/communications systems is presented. To increase the gain and bandwidth simultaneously, the triple transmission lines (TTLs) method has been used. With this method, the frequency ranges of 1.7–2.5 and 5.4–5.95 GHz are covered with dual-band responses. Also, the simulated

This paper reports on quasi-elliptic dual-band bandpass filters (BPFs) that were designed for the Filter Student Design Competition of the 2019 European Microwave Week. The proposed lumped-element (LE) BPF concept is based on two dual-band transversal cells and one multi-resonant cell that allow the realization of symmetric and asymmetric dual-band transfer functions shaped by six poles and five transmission

The effective resistivity (ρeff) is a figure of merit commonly used to assess the radio-frequency performance of a substrate from the measurements of coplanar waveguide lines. For highly resistive substrates, such as the trap-rich (TR) substrate, the extracted ρeff decreases by several orders of magnitude at millimeter-wave frequencies. The explanation for this decay is twofold. First, the imaginary

This paper presents the filter design in the student design competition of EuMW 2019. This contest motivates students for the design and implementation of a dual-band bandpass filter able to get outstanding performance, where different implementation technologies, such as microstrip, coplanar, multilayer microstrip, substrate integrated waveguide, and some others can be effectively employed. Filters

The purpose of this paper is the design of a novel single layer reflectarray antenna in X-band, which can electronically steer the antenna beam and change its polarization. Each antenna element includes a circular patch and rings around it, equipped with two varactor diodes, which are positioned perpendicular together to create a circular polarization. First, using these elements, a circular polarized

This study presents a simple switched-band impedance transformer using microstrip lines. The proposed circuit is suitable for loads with frequency-dependent complex impedances at two arbitrary operating frequencies. The transformer comprises two cascaded microstrip lines and two detachable shunt stepped-impedance stubs, which are separately connected to the main line via switching diodes such that

Continuous mode class-J radio-frequency (RF) power amplifier is a promising technique that extends the operating bandwidth of the conventional class-B power amplifier. However, the maximum theoretical efficiency is limited to that of the class-B power amplifier. In this paper, an enhanced mode of operation for the class-J power amplifier is proposed by incorporating a third harmonic voltage component

The purpose of this paper is to disclose improved crystal based frequency source system covering design techniques and experimental methodologies for the stabilization of phase noise performance of X-band phase-locked loop (PLL) at 10.6 GHz. Phase noise performance of PLL-based unit under test (UUT) is prone to disturbance occurred in random vibration profile frequency spectrum. UUT self-resonance

Microstrip and stripline losses in Method of Moments (MOM) calculations have an error arising from the large current density at the strip edges, characterized by an integration limit (W/2-d) in the equation for current density in thin strips (width W), where d is a fitting parameter. It depends primarily on the width of the MOM subsection on the edge of the strip. By comparing with the integration

In mathematical definition, a fractal is a self-similar subset of Euclidean space whose fractal dimension strictly exceeds its topological dimension which in turn involves a recursive generating methodology that results in contours with infinitely intricate fine structures. Fractal geometry has been used to model complex natural objects such as clouds coastlines, etc., that has space-filling properties

In this paper, a novel approach of high-accuracy calibration (HAC) method is employed to improve the resolution of tumor detection within a fibro-glandular breast model, and also an improved 3D back-projection approach to scan each focal point inside of the breast is presented. For these purposes, a simulated hemispherical setup of a multi-static array with a modified UWB bowtie antenna is applied

In this paper, a triple-band bandpass filter using a multi-mode half-mode substrate integrated waveguide (HMSIW) cavity is presented. In this design, back-to-back connected half-mode defected ground structure (DGS) is loaded into the HMSIW cavity, which generates the first passband. The first four modes of HMSIW cavity are TM110, TM120, TM310, and TM320. They have been used to generate second and third

A novel waveguide resonator is proposed in the paper. The resonator is composed of three rectangular partial-height posts inserted along a rectangular waveguide cross-section. A pair of lateral posts is mounted symmetrically whereas the third antipodal post is centered. The resonator enables bandreject, singlet-type, and pseudoelliptic responses. The operating regimes are achieved by a manipulation

The design of proper antenna element (AE) for microwave-based head imaging or brain stroke detection is a crucial challenge in the development process of microwave imaging (MWI) systems. The main purpose of this paper was to design, fabricate, and experimentally verify the compact and dimensions-reduced H-slot antenna suitable for the new generation of multichannel MWI system for brain stroke detection

This study provides an analytic method for the calculation of the cutoff frequencies and waveguide modes of a partially filled eccentric coaxial cable. The method is based on the expressions of the involved electromagnetic fields in bipolar coordinate systems and the validity range of the solution is discussed. It is shown how the waveguide geometry and dielectric parameters may be selected to engineer

This paper presents the integration and channel characterization of a highly integrated dual-band digital beamforming space-borne synthetic aperture radar (SAR) receiver. The proposed SAR sensor is a low-cost, lightweight, low-power consumption, and dual-band (X/Ka) dual-polarized module ready for the next-generation space-borne SAR missions. In previous works, by the authors, the design and experimental

Airbus Italia recently developed enhanced passive components as key elements for its telecommunication Ku-band antenna product lines, tailored to reconfigurable payloads. This paper describes the design and qualification of a dual linear polarization Ku-band-radiating chain, developed for the DRA receive (Rx) active antennas embarked on the Eutelsat Quantum satellite. The feed chain covers the entire

Multiple antennas and multiple radio frequency (RF) chains in both the transmitter and receiver are required in conventional radio systems employing the multiple-input multiple-output (MIMO) method. This paper presents an experimental investigation of a beam-steering time-modulated MIMO receiver with a single RF chain. Implementation of the receiver is based on a time-modulated antenna array (TMAA)

In this paper, the design of a miniature antenna dedicated to the detection of airliners through the demodulation of Automatic Dependence Surveillance-Broadcast system (ADS-B) signals is presented. This antenna is designed for being embedded on the top of a drone in order to detect and avoid collisions with airliners. This antenna consists of an array of Planar Inverted-F Antennas, a quadrature feed

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

This paper presents an efficient approach for the design of a non-uniform single ring circular antenna array (CAA) for the synthesis of the optimal far-field radiation pattern. A recently proposed meta-heuristic-based optimization technique known as ant lion optimization (ALO) is applied in this paper to determine the optimum set of current amplitude excitation weights and the inter-element distance

This research involves a compact wideband circularly-polarized antenna array, which consists of a sequential rotating phase feed network, 2 × 2 mushroom-type metamaterial (MTM) unit, and so on. Each antenna array unit contains a microstrip feedline, an L-shaped slot antenna, and so on. The MTM-based antennas were incorporated with a sequential-phase network of sequentially rotated series-parallel feed

This paper presents a theoretical and experimental analysis of the capabilities of the dual-input Doherty power amplifier (DPA) architecture to mitigate efficiency and output power degradations when used in a mismatched load environment. Following a simplified linear piecewise approach, an analytical demonstration is proposed to derive optimal radio frequency drives applied to the Auxiliary path of

In this work, the scattering characteristics of 3D-printed samples are being investigated by using a single-polarized and a cross-polarized radar system. The 3D-printed technology participates in a wide range of applications nowadays. The idea of synthetic aperture radar (SAR) has been utilized to investigate the reflected electromagnetic energy from the 3D-printed samples by setting each of the radar

In this research, a compact dual band-notched (DBN) super-wideband (SWB) coplanar waveguide-fed antenna with high bandwidth (BW) dimension ratio of 7427.4 has been presented. The proposed antenna covers a very wide frequency range from 2.8 to 40 GHz (BW ratio of 14.28:1) with |S11|<−10 dB. The overall antenna size is 20 × 14 × 1.6 mm3 which consists of an FR4 substrate with a dielectric constant of

An inspired metamaterial-based highly efficient monopole antenna displaying wide-/dual-band resonances along with self-filtering properties is presented. The monopole has high out-of-band suppression characteristics that lead to very close to 0 dB band-stop between the antenna dual resonant bands. The antenna operates at the two WLAN services of 2.65–3.25 and 5–7 GHz with stopband with total reflection

This paper considers the ability of polarization measurements for microwave remote sensing of clouds and precipitation. The simulation of reflections from liquid hydrometeors with a multi-polarization radar system is presented. The mathematical expression of energy received by a radar antenna with arbitrary polarization is obtained. The simulation of the energy redistribution of the signal reflected