Article Frontmatter was published on May 1, 2021 in the journal Frequenz (volume 75, issue 5-6).

This paper presents a compact and the low-cost coupled line band-pass filter with application to future generation millimetre-waves and 5G communications. The proposed approach of the filter design is based on the coupled-line and centre tapped upper and lower stepped impedance resonators. These resonators generate the sharp rejection, wide bandwidth, and abet to realize the compact filter. A detailed

This paper presents a novel design of rigid coaxial line based variable stub tuner. It incorporates controlled drive for the movement of shorting ring along the length of the stub inside the coaxial line. The ring is housed inside stub through linear slot over the coaxial conductor. Inbuilt slot at outer conductor of coaxial line introduces undesirable discontinuity which deteriorates the performance

In this paper, two types of coaxial coupler and waveguide coupler for different frequency helix traveling wave tubes (TWTs) are designed, fabricated and cold tested. The coaxial coupler includes of window ceramic and RF transformer section. At present multi-section impedance transformer design approach is used for wideband helix TWTs. In any helix TWT, impedance of the source is transformed to the

For the next generation wireless networks, backhaul links with data rates of several Gbit / s are required. Line-of-Sight-MIMO with optimally arranged antennas can exploit the full multiplexing gain of orthogonal MIMO streams to achieve high throughput, as shown in recent works utilizing the 60 GHz mm wave band. In contrast, conventional MIMO systems operating at sub-6 GHz carrier frequencies, as utilized

Here, a planar Ultra-Wideband (UWB) wearable Multiple Input Multiple Output (MIMO) antenna is designed for on-arm wearable Wireless Body Area Network (WBAN) applications. This antenna is designed on a 100% cotton cloth substrate. The two-port MIMO antenna has a dual spinning wheel shape like radiators with the partial ground and microstrip feedings. The two partial grounds are connected to a rectangular

In this article, cross-shaped metallic parasitic strips based two radiator element multiple-input multiple-output (MIMO) dielectric resonator antenna (DRA) is excited by quadrature wave transformer microstrip feedline, designed, simulated and fabricated for ultra-wideband (UWB) applications. The proposed MIMO antenna structure is implemented with the help of two rectangular-shaped radiator elements

A two-port multiple input multiple output (MIMO) dielectric resonator antenna is proposed where two orthogonally connected feed lines are combined to unite two orthogonally produced modes. The feed lines build a hybrid network. The backplane is defected by a circular defected ground structure (CDGS), which is extended by two rectangular slits placed orthogonally with the input ports. The antenna uses

Conical Terahertz DRA (dielectric resonator antenna) have been designed and investigated at terahertz spectrum i.e. 10 THz. Lower terahertz frequency band is useful for high data speed communication and upper band is used for optical sensors and free space wireless communications. Novelty in this work is to open up research in. terahertz. A unique geometry based dual band terahertz DRA with mathematical

We present the design of a compact tri-band adhesive planar antenna which operates as a gateway for biomedical applications. Operating in the Industrial, Scientific and Medical (ISM) band (2.4–2.5 GHz), the Institute of Electrical and Electronics Engineers (IEEE) 802.15.6 Wireless Body Area Network Ultra-Wide Band (WBAN UWB) (3.1–10.6 GHz) and the IEEE 802.11 Wireless Local Area Network or WLAN (WLAN)

A slot loaded annular sector microstrip antenna having a pentaband operation is presented. The antenna has six resonant frequencies and the fourth band occurs between the fourth and fifth resonance. The radiation pattern is linearly polarized at all the frequencies. The radiation is broadside directed at the first three bands, tilted at the fourth and split at the fifth band. The resonant frequencies

Article Frontmatter was published on March 1, 2021 in the journal Frequenz (volume 75, issue 3-4).

A novel printed and compact profile monopole antenna with hybrid reconfigurability structure for switching the resonant frequency and direction of maximum radiations is proposed in this research work. A novel mathematical model for the architecture of Reconfigurable Patch Antenna (RPA), considering input impedance, bandwidth, antenna gain, antenna efficiency and resonant frequency is proposed. For

In this article, the design of a radiation beam-reconfigurable antenna using the reflector pins is presented. The reflector pins make a short or open connection with the ground, via switches and Plated Through Hole (PTH), which helps in controlling radiation characteristics of the proposed antenna. This design contains a simple 3D printed Cylindrical Dielectric Resonator Antenna that is located at

A Triple-band Multiple-Input-Multiple-Output (MIMO) antenna for 5G mobile terminal applications is proposed in this paper. The design comprises four-port/two resonators, each having two concentric circular slot ring radiators etched on a ground plane of size 50 mm ×${\times}$ 50 mm. The antenna is fed by perpendicularly arranged 50 Ω microstrip line feeds on the top layer. Decoupling techniques were

In this paper a coplanar waveguide feed (CPW) monopole antenna backed with artificial magnetic conductor (AMC) structure for efficient radiation has been presented for off-body wearable applications. A split ring resonator (SRR) having thiner and longer lines to produce higher inductance and six splits with smaller gaps for high capacitance have been placed underneath CPW fed monopole to achieve resonance

This paper presents electrical equivalent circuit modelling of various fractal-based UWB antennas. Three different designs have been discussed here as case studies, whose characteristics are diversified in nature. Even the implemented fractal geometries are also unique in nature for these antenna problems. An easy circuit model for each antenna structure is proposed which deciphers the insight device

In this article, broadband gain enhancement of an ultra-wide band (UWB) antenna is achieved by using 4 × 4 array of a wideband negative refractive index (NRI) metamaterial as a reflector layer. A novel shaped metamaterial sized 14.8 × 14.8 mm 2 with double negative (DNG) characteristics in three frequency regions has been fabricated on a flexible FR4 with 0.25 mm thickness. The proposed metamaterial

In this paper, an Archimedean spiral antenna-based biosensor has been proposed for the early detection of breast tumor. By monitoring the variation of S 11 over 1–3.5 GHz frequency range, the proposed scheme can identify the tumor location, as well as distinguish the types of tumor (benign or malignant) based on shapes and dielectric properties contrast. To validate the concept, full wave simulation

In this paper, a methodical approach for the in-situ monitoring of the mechanical wear of electrical conductors is presented. The state of life can be assessed by means of the characteristic attenuation of an applied high-frequency alternating current. The advantages of this approach include its non-destructive nature and the applicability to installed and otherwise inaccessible conductors.

In this article, Terahertz spherical dielectric resonator antenna (DRA) is mathematically formulated and simulated at 511 THz for LiDAR and retinal photoreceptor applications. Titanate DR element is used at optical design frequency. It is validated with good S11, radiation pattern and 5.6 dBi gain plots using HFSS simulator. Unique mathematical formulation on super directivity and radiated states is

Journal Name: Frequenz Volume: 75 Issue: 1-2 Pages: i-iii

In this paper, a balanced-to-balanced (BTB) branch-slotline directional coupler (DC) is firstly presented, which can realize an arbitrary power division ratios (PDRs). The coupler is composed by microstrip-to-slotline (MS) transition structures and branch-slotline coupled structures. The single-ended to balanced-ended conversion is simplified and easy to implemented by the MS transition structures

In the present article authors propose the design and analysis of an octagonal shape multiband metamaterial loaded antenna with implementation of hybrid fractal geometry for wireless applications. Multiband features in the antenna structure is realized by applying the slotted and hybrid fractalization of Moore and Koch curve approach in radiating section along with introduction of two metamaterial

Smartdielectric resonator antenna (DRA) having beam control mechanism is anew area to be explored by antenna researchers. Proposed new geometry DRA has low loss, design flexibility, high efficiency, compact size and desired radiated beam control. Developing beam control in new geometry DRAs is investigated for the first time in this letter. Unique technique for beam control and beam width control is

In this paper, the scanning rate (SR) is enhanced for substrate integrated waveguide (SIW) based periodic leaky wave antenna (LWA) with continuous beam scanning. Delay line is inserted in the SIW based periodic LWA to modify the group delay profile which in turn increase the SR of the SIW based periodic LWA. Addition of the delay line enhances the SR of the SIW LWA to approximately three times from

Journal Name: Frequenz Volume: 74 Issue: 11-12 Pages: i-iii

This paper presents a novel E armed dipole antenna for System On Chip (SOC) applications in the Sub-THz frequency band. The antenna is printed on a corrugated silicon substrate which suppresses surface waves and provides high efficiency and gain. The corrugated substrate also provides a better impedance matching. The antenna has a simulated gain of 5.4 dBi and 3 dB beam-width of 83.5 degree. The proposed

A multi spiral split ring resonator based sensor is proposed for the characterization of the dielectric properties of a water ethanol mixture. The use of a narrowed microstrip line to excite the multi spiral resonator allows enhancement of excitation current and increase the sensitivity of the sensing area. Good agreement will be presented between theoretical and measured electrical parameters of the

The performance of a generalized mixed free-space-optical (FSO)/millimeter (mm)-wave radio-frequency (RF) two-hop link model is investigated in this work. The first-hop FSO channel considers the influence of path loss, atmospheric turbulence which is modeled by the gamma–gamma (GG)-distribution, and generalized misalignment errors which incorporate the effects of non-zero boresight errors, different

A 3 × 3 slotted circular Electromagnetic Band gap based Metasurface (SCEBG-MS) has been presented in this article, which enhances the performance of a circularly polarized (CP) patch antenna by improving its impedance bandwidth, axial ratio bandwidth and gain. The proposed antenna is having a low profile of 0.065 λo (λo is the free-space wavelength at center frequency of 6.16 GHz) with ground size

Compact antennas with robust on-body performance are achieving more interest for wearable sensor nodes. In this paper, a modified aperture coupled multiple input multiple output (MIMO) antenna operating at 2.45 GHz industrial scientific and medical (ISM) band is presented for wearable devices. 8-shaped radiator with L-shaped ground slot is used to miniaturize the antenna dimensions. A dielectric reflector

A low profile Circular Microstrip Patch Antenna (CMPA) with radius 5 mm has been designed to generate two resonant frequency bands that can be used for WLAN 5.2 (5.15–5.25) GHz, Wi-Fi (5.725–5.850) GHz and Dedicated Short-Range Communications (DSRC) (5.85–5.925) GHz application bands. The designed antenna has been slitted with two slits and a stub has also been attached resulting in an additional resonant

In this paper a wideband, flexible, and novel structured double negative (DNG) metamaterial is designed for S, C, X, and Ku microwave applications. The 12 mm × 12 mm sized metamaterial is fabricated on a flexible FR4 substrate with thickness 0.25 mm. The metamaterial shows a total wide DNG region of 8.2 GHz (3.8–4.3 GHz and 6.8–14.5 GHz). The transmission coefficient of the unit cell has a total band

Miniaturizing the microwave circuits for micro-satellite platform has been one of the development trends in microwave remote sensing. A novel 89/118/166/183 GHz frequency dividing network is proposed in this paper which includes two stages: the first stage is an F-G band diplexer that separate 89/118 GHz signals from 166/183 GHz signals. The measured typical transmission loss is 1.5 dB from 83.75 to

The all-optical logic gates have become an important key enabling in optical integrated circuits and find applications in optical networks. In this paper, we introduce new complete series of optical logic gates using photonic crystals. These designs formed by compilation with interference based defect and resonance phenomenon. The proposed work based on two dimensional square lattices by putting gallium

Journal Name: Frequenz Volume: 74 Issue: 9-10 Pages: i-iii

In this article, a simple design of stacked radiating system with enhanced gain, impedance bandwidth, and radiation efficiency for mobile base station application is presented. The proposed antenna consists of a driven patch with a semicircular parasitic patch printed on the bottom layer and five parasitic patches printed on the top layer. The driven patch is feed by a co-axial probe and both the layers

This paper presents a concurrent dual-band radar system for noncontact tracking of vital signs (e.g., respiration and heartbeat), and indoor short-range localization. The proposed sensor, which has been achieved with our own customized concurrent dual-band subsystems, operates at 1.67 and 2.06 GHz synchronously. Based on the Doppler principle, tiny vital signs are obtained by analysis of spectrum of

In this paper the design and analysis of two dimensional photonic crystals based all optical AND logic gate is investigated. A logic gate implements a Boolean function and thus performs a logical operation on one or several logic inputs in order to produce a single logic input. The proposed all optical AND gate is designed with line and point defect using a hexagonal lattice with “Y” shaped defect

In this paper, a novel technique based on transmission-only measurements is proposed to determine complex permittivity and permeability of low-loss materials. The proposed method removes the influences of the sample thickness and avoids the resonances in the extracted parameters. Both the experiment and simulation are applied to present the advantages of the proposed method. Compared with the well-known

In this paper, a novel approach to achieve multiband antenna operation using metamaterial based resonant structures is presented. Multiband antenna operation is achieved by employment of complementary split ring resonators (CSRR) printed in the ground plane. The CSRRs resonate at different frequencies according to their optimized dimensions. Proposed approach features simple design and fabrication

Mode-division multiplexing (MDM) in silicon-on-insulator platform is an emerging technology to increase the channel number of a single wavelength carrier by the number of modes and consequently increase the transmission capacity of on-chip optical interconnects. We propose and theoretically demonstrate a multimode branching structure based on the truncated Eaton lens. The proposed T-junctions efficiently

A half mode substrate integrated waveguide (HMSIW) based leaky wave antenna (LWA) featuring low cross-polarization is proposed in this paper. The umbrella-shaped slot (the combination of longitudinal and transverse slots) is etched on the top layer of HMSIW LWA to get the efficient broadside radiation. The scanning range is obtained from −47° to +30° in a frequency range of 8.3 to 15.1 GHz. The cross-polarization

In this paper, a cross dipole antenna is proposed, designed, and developed for satellite communication applications. The design incorporates an alternative feeding mechanism of the coaxial/probe feeding technique with balun. The primary objective of this paper is to develop the high gain antenna with an array configuration for satellite communication. The performance parameters of an antenna such as

Journal Name: Frequenz Volume: 74 Issue: 7-8 Pages: i-iii

In this paper, we study the optimization of two tilt angles corresponding to two antenna arrays in each base station (BS) of a massive multiple-input multiple-output system. We consider two scenarios with perfect channel state information (CSI) and imperfect CSI. In the limit of the number of the BS antennas, the channel orthogonality is employed to derive the limit and the lower bound of the throughputs

In this paper a Quad-band diversity antenna with a small size of 48 × 28 × 0.8 mm3 printed on FR4 substrate is presented that consists of two same pentagonal-shaped patch elements. Four arc-shaped slots in the radiating elements are introduced to obtain the quad-band operation with good return loss. The antenna is designed for covering 5.91 GHz in IEEE 802.11 b/g/n standards, 7.40 GHz in C-Band, 9

In this study, estimation of Ultra-Wideband (UWB) characteristics of microstrip elliptic patch antenna is investigated by means of k-nearest neighborhood algorithm. A total of 16,940 antennas are simulated by changing antenna dimensions and substrate material. Antennas are examined by observing Return Loss and Voltage Standing Wave Ratio (VSWR) characteristics. In the study, classification of antennas

In this paper, parallel coupled meander lines (PCML) composite right/left-handed transmission line (CRLH-TL) based symmetrical quasi-0 dB coupled-line coupler is presented. Proposed coupler shows measured backward wave coupling level of 0.81 dB at frequency of 6.17 GHz with 3 dB fractional bandwidth (FBW) of 12.64%. Throughout the 3 dB frequency range (5.78–6.56 GHz), isolation and insertion loss of

This paper presents a modern compact quad-band bandpass filter (BPF) using dual-mode stub loaded half wave (λ/2) resonators, where a couple of directly fed resonators are loaded with two identical inner resonators such that the direct fed resonators will act as feeding structure for the loaded resonators. Based on the proposed stub loaded resonators, a modern filter with seven transmission zeros (TZs)

A novel scheme to suppress the remnant mode conversion noise with a surface mount device (SMD) capacitor on dual back-to-back bent differential lines is proposed. To suppress the remnant mode conversion noise, an additional SMD capacitor is loaded on the differential lines between two bends to equalize even- and odd-mode velocities. The mode conversion noise suppression characteristics of the proposed

In this paper, a novel compact UWB antenna with variable notched band characteristics for UWB applications is presented. The designed antenna primarily consists of an adjusted elliptical shaped metallic patch and a partial ground plane. The proposed antenna has a compact size of only 17 × 17 mm2. The suggested antenna covers the frequency range from 3.1 GHz to 12 GHz. A single notched band has been

A broadband circularly polarized slotted square patch antenna with horizontal meandered strip (HMS) is presented and studied. The HMS feeding technique provides the good impedance matching and broadside symmetrical radiation patterns. A set of cross asymmetrical slots are etched on the radiating patch to realize the circular polarization. An electrically small stub is added on the edge of the antenna

Inspired by the theory of leaky wave antenna, a broadband and wide-angle frequency scanning antenna is proposed in this paper. My goal is to trade a narrow frequency band for a wide-angle beam scanning. Since the dispersion of spoof surface plasmon polariton (SSPP) mode slow-wave possesses larger gradient than that of the waves in the air, the metallic corrugated line (MCL) is adopted for energy transmission

This article presents a design of highpass filter (HPF) for millimeter-wave (mm-wave) applications using a square complementary split-ring resonator (SCSRR). A miniaturized size HPF filter is obtained by overlapping the Right-Hand (RH) and Left-Hand material. The arrangement of inter-digital parallel coupled capacitor and SCSRR offers low insertion loss, high selectivity with a sharp roll-off factor

In this paper, a new Wilkinson Power Divider ‎‎(WPD) using open and short stubs is proposed. ‎Open and short stubs are utilized instead of 1/4 wave transmission lines in initial ‎structure to achieve harmonics suppression. The proposed WPD is designed for ‎operational frequency of 0.9 GHz and creates 3 transmission ‎zeros at 1.8 GHz, 2.7 GHz and 3.6 GHz, for suppressing second, third and fourth harmonics

Journal Name: Frequenz Volume: 74 Issue: 5-6 Pages: i-iii

In this paper, a novel tri-band reconfigurable patch antenna with simple structure is presented. By changing the on-off state of only two PIN diodes, the antenna can operate in three bands, namely X-band, Ku-band, and Ka-band. The overall size of the antenna is 0.24λL × 0.5λL × 0.019λL, where λL is the free-space wavelength of the lowest operating frequency. A prototype is fabricated and measured to

This research proposes a novel circularly polarized (CP) reconfigurable microstrip loop antenna for 2.4–2.5 GHz advanced wireless communication using two parasitic patches and two PIN diodes. The reconfigurable antenna can alternate between right hand circular polarization (RHCP) and left hand circular polarization (LHCP) at the main beam by manipulating the ON/OFF status of the PIN diodes. Simulations