In this paper, the design and analysis of a complementary Sierpinski Knopp fractal antenna are presented. It is realized by applying the Sierpinski Knopp space-filling curve on the basic square monopole antenna. The performance metrics of the antenna such as (reflection coefficient), voltage standing wave ratio, radiation pattern, gain and current distribution at resonant frequencies are analyzed

In this paper, a compact circularly polarized quadrifilar antenna with planar inverted-F antenna (PIFA) elements is presented. The proposed antenna consists of four PIFA elements and a Wilkinson divider-based feed network fabricated on FR-4 substrate ( = 4.4, loss tangent = 0.02, thickness = 1.6 mm). The total size of the antenna is 120 × 120 × 13.2 mm. Impedance matching with a reflection coeffic

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 r

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 reflect

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 pro

The microwave waveguide and resonator methods are compared as applied to the experimental determination of the dielectric properties of high loss liquids. A differential microwave waveguide cavity for measuring high loss liquids complex permittivity in a small volume has been designed and studied. This cavity consists of two circular waveguide cells with central rods made of quartz and surrounded

From the prevention of natural disasters such as landslide and avalanches, to the enhancement of energy efficiencies in chemical and civil engineering industries, understanding the collective dynamics of granular materials is a fundamental question that are closely related to our daily lives. Using a recently developed multi-static radar system operating at 10 GHz (X-band), we explore the possibil

Structures of tunneling nanotubes (TNTs) of the circular cross-section of 50 and 200 nm and length up to 1 mm form a communication system between cells. While transport of material such as endocytic vesicles, mitochondria, proteins, cytoplasmic molecules, etc., is experimentally proven, a possible transfer of electric and electromagnetic energy across TNTs corresponding to electrotechnical process

The design, simulations, and optimized results for a novel low specific absorption rate (SAR) monopole antenna on a single artificial magnetic conductor (AMC) cell are described in this paper. Simulated results show a reduction close to 70% in the 1 g ps SAR for the developed monopole antenna with the AMC in comparison to the monopole antenna without AMC. This allows higher radiation efficiency, b

In this paper, a differential microfluidic sensor and comparator based on a pair of microstrip lines loaded with dumbbell-shaped defected ground structure resonators is applied to the characterization of electrolyte concentration in samples of horse urine. Since variations in the total electrolyte content in urine may be indicative of certain pathologies, the interest is to use the device as a com

A solution to the problem of Gaussian beam scattering by a circular perfect electric conductor coated with eccentrically anisotropic media is presented. The incident Gaussian beam source is expanded as an approximate expression in the simple form with Taylor's series. The transmitted field in the anisotropically coated region is expressed as an infinite summation of Eigen plane waves with differen

This work examines the impact of the inverse chirp -transform (ICZT) for frequency-to-time-domain conversion during image reconstruction of a pre-clinical radar-based breast microwave imaging system operating over 1?8 GHz. Two anthropomorphic breast phantoms were scanned with this system, and the delay-multiply-and-sum beamformer was used to reconstruct images of the phantoms, after using either t

This literature presents a comprehensive, technical review of circularly polarized (CP) antennas for different applications in wireless communication, emphasizing on the recent developments in the concerned research. The article also presents a comparative study of various works reported in the open literature, with an aim to highlight the contribution of CP antenna systems in the chronological de

Hyperthermia (i.e. heating of tumor tissue to 40?43°C) is used in clinical oncology to enhance the therapeutic effect of chemotherapy and radiotherapy. Many tumor sites are heated either by a single RF or MW antenna positioned on the tumor location, or by a phased array positioned around the patient. Superficial tumors are generally heated with MW antennas (434?2450 MHz) and deep-seated tumors wit

A bidirectional dielectric resonator (DR) antenna array using back-to-back quasi-Yagi antenna configuration is proposed and implemented for the first time. The DR operating at higher-order TE mode is used as a magnetic dipole, applying for the driver of quasi-Yagi antenna. Due to the high-order mode employment, the antenna gain can be enhanced. By partially loading the metallic strip on the side w

To prevent far-field radiation characteristics degradation while increasing bandwidth, an attempt has been made to design and fabricate a microstrip antenna. An electromagnetic band gap (EBG) structure, including a layer of a metallic ring on a layer of Rogers 4003C substrate, is used. For a better design, a patch antenna with and without the EBG substrate has been simulated. The results show that

The temperature dependence of the dielectric parameters of tissues and tissue-mimicking phantoms is very important for non-invasive temperature measurement in medical applications using microwaves. We performed measurements of this dependence in the temperature range of 25?50°C using distilled water as a reference liquid commonly used in dielectric property studies. The results were compared with

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 band

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

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 , we demonstrate an average efficiency improvement f