A Jug-Shaped CPW-Fed Ultra-Wideband Printed Monopole Antenna for Wireless Communications Networks

A type of telecommunication technology called an ultra-wideband (UWB) is used to provide a typical solution for short-range wireless communication due to large bandwidth and low power consumption in transmission and reception. Printed monopole antennas are considered as a preferred platform for implementing this technology because of its alluring characteristics such as light weight, low cost, ease of fabrication, integration capability with other systems, etc. Therefore, a compact-sized ultra-wideband (UWB) printed monopole antenna with improved gain and efficiency is presented in this article. Computer simulation technology microwave studio (CSTMWS) software is used to build and analyze the proposed antenna design technique. This broadband printed monopole antenna contains a jug-shaped radiator fed by a coplanar waveguide (CPW) technique. The designed UWB antenna is fabricated on a low-cost FR-4 substrate with relative permittivity of 4.3, loss tangent of 0.025, and a standard height of 1.6 mm, sized at 25 mm × 22 mm × 1.6 mm, suitable for wireless communication system. The designed UWB antenna works with maximum gain (peak gain of 4.1 dB) across the whole UWB spectrum of 3–11 GHz. The results are simulated, measured, and debated in detail. Different parametric studies based on numerical simulations are involved to arrive at the optimal design through monitoring the effects of adding cuts on the performance of the proposed antennas. Therefore, these parametric studies are optimized to achieve maximum antenna bandwidth with relatively best gain. The proposed patch antenna shape is like a jug with a handle that offers greater bandwidth, good gain, higher efficiency, and compact size.

A Novel Wideband Coplanar Waveguide (CPW) Fed Antenna for Energy Harvesting at 2.45 GHz

Conversion of electric power from a high voltage to a low voltage causes power losses that also require efficient circuit design techniques to be implemented for durability of a system. Energy harvesting techniques have been implemented to cater to the power demand of low power electronic devices using electromagnetic, electrostatic, and other related technologies. This paper represents the compact design of an antenna system tuned at 2.45 GHz for radio frequency energy harvesting applications. The simulation results achieve a better gain of 5.4 dB along with enhanced radiation patterns. Impedance matching for 50 Ohm is implemented using a high frequency structure simulator (HFSS). The results of the antenna gain, VSWR, and radiation efficiency are compared with the literature. Furthermore, the size of the antenna system has great significance in medical and military related applications; this aspect is also considered in this design and overall, a 20 mm × 37 mm compact antenna is achieved by using mm wave considerations. This antenna design can be embedded in the wireless sensor network (WSN), RFID, and IoT related application to generate the required power required. Mostly, WSN nodes currently use traditional batteries that need to be replaced after some time. As in most cases, WSN nodes are scattered in wide geographical areas, so maintaining the power to these systems becomes challenging. RF energy harvesting provides a solution in these cases where wind, vibration, and solar sources are scarce. The simulated impedance bandwidth is found to range from 1.1 GHz to 5.2 GHz within the acceptable VSWR values.

Compact Broadband Circularly Polarized CPW-Fed Antenna with Characteristic Mode Analysis

A compact circularly polarized (CP) antenna is proposed for low-profile and wideband operation based on characteristic mode analysis (CMA). A ring patch with a gap and two arc-shaped metallic stubs as the radiator is analyzed and optimized by CMA to figure out the orthogonal modes and operating frequency band for potential good axial ratio (AR) performance. The studies of these CP modes provide a physical insight into the property of broadband circular polarization. Such an in-depth understanding paves the way for the proposal of novel CP antenna with separation between the design of radiator and feeding network. A 50-Ω coplanar waveguide (CPW) is introduced and placed appropriately to excite the desired modes based on the information from CMA, which employs two asymmetric ground planes to improve the performance in terms of AR and impedance matching. The antenna with a compact size of 0.71λ0 × 0.76λ0 × 0.038λ0 (λ0 is the free-space wavelength at the center frequency of the 3-dB AR bandwidth) is fabricated and measured for validation. The realized gain varies from 1.6 to 3.1 dBic over the operating bandwidth characterized by the measured 10-dB impedance bandwidth of 83.8% (3.98–9.72 GHz) and 3-dB AR bandwidth of 70.3% (4.59–9.57 GHz), respectively.

Suppression of spin rectification effects in spin pumping experiments

Spin pumping (SP) is a well-established method to generate pure spin currents allowing efficient spin injection into metals and semiconductors avoiding the problem of impedance mismatch. However, to disentangle pure spin currents from parasitic effects due to spin rectification effects (SRE) is a difficult task that is seriously hampering further developments. Here we propose a simple method that allows suppressing SRE contribution to inverse spin Hall effect (ISHE) voltage signal avoiding long and tedious angle-dependent measurements. We show an experimental study in the well-known Py/Pt system by using a coplanar waveguide (CPW). Results obtained demonstrate that the sign and size of the measured transverse voltage signal depends on the width of the sample along the CPW active line. A progressive reduction of this width evidences that SRE contribution to the measured transverse voltage signal becomes negligibly small for sample width below 200 μm. A numerical solution of the Maxwell equations in the CPW-sample setup, by using the Landau-Lifshitz equation with the Gilbert damping term (LLG) as the constitutive equation of the media, and with the proper set of boundary conditions, confirms the obtained experimental results.

Performance Improvement of Substrate Integrated Cavity Fed Dipole Array Antenna Using ENZ Metamaterial for 5G Applications

This paper exhibits a high-gain, low-profile dipole antenna array (DAA) for 5G applications. The dipole element has a semi-triangular shape to realize a simple input impedance regime. To reduce the overall antenna size, a substrate integrated cavity (SIC) is adopted as a power splitter feeding network. The transition between the SIC and the antenna element is achieved by a grounded coplanar waveguide (GCPW) to increase the degree of freedom of impedance matching. Epsilon-near-zero (ENZ) metamaterial technique is exploited for gain enhancement. The ENZ metamaterial unit cells of meander shape are placed in front of each dipole perpendicularly to guide the radiated power into the broadside direction. The prospective antenna has an overall size of 2.58 λg3 and operates from 28.5 GHz up to 30.5 GHz. The gain is improved by 5 dB compared to that of the antenna without ENZ unit cells, reaching 11 dBi at the center frequency of 29.5 GHz. Measured and simulated results show a reasonable agreement.

MIMO CPW-Fed Bent Antenna Based USB Dongle for ECMA-368 WPANs

A multiple-input-multiple-output (MIMO) ultra-wideband (UWB ) printed bent antenna, suitable for MB-OFDM ECMA-368 system integration with the wireless universal serial-bus (WUSB) dongle is proposed. The antenna consists of two antenna elements with an overall area of 18 X 53 mm2. Each antenna element is a simple modified folded-monopole fed by a coplanar waveguide (CPW). The design process of proposed MIMO UWB CPW-fed bent antenna configuration is presented in four simple steps. Experimental results show that the proposed design has a good impedance bandwidth in the range of 2.95–18.55 GHz with 147.2% fractional bandwidth (FBW). Moreover, the proposed antenna enjoys, low envelope correlation coefficient (ECC), good diversity gain (DG), low total active reflection coefficient (TARC) and omnidirectional radiation patterns. The bit error rate (BER) of the overall MB-OFDM ECMA-368 system with the existence of the proposed MIMO UWB CPW-fed bent antenna is evaluated in more realistic transmission channel scenario by using the extracted transmitting and receiving UWB antennas transfer functions.

Design of a 1×2 CPW Fractal Antenna Array on Plexiglas Substrate with Defected Ground Plane for Telecommunication Applications

In this paper, a fractal antenna array for telecommunication applications is presented. The proposed antenna array is realized on a Plexiglas substrate, has 1×2 radiating elements, and dimensions of 170mm×105mm. The antenna array is composed of two Koch Snowflake patches and is fed by a Coplanar Waveguide (CPW) transmission line. Radiating elements and the ground plane are printed on the top side of the substrate. Defected Ground Structure (DGS) technique is employed to enhance the bandwidth and improve the impedance matching. The proposed antenna array operates at two frequency bands, 1.08-1.32GHz covering the GPS band and 1.7-3.7GHz covering the GSM 1800/1900, UTMS, Bluetooth, LTE, and WiMAX bands. In addition, the antenna has a good performance with efficiency and peak gain of 82% and 6.3dB respectively. These characteristics allow the antenna to be an attractive candidate for telecommunication systems. Design and analysis of different structures were carried out with Ansys HFSS.

High-performance inline RF MEMS switch for application in 5G mobile networks

This article presents the results of the design and analysis of a radio-frequency switch made using microelectromechanical systems technology. The device is the capacitive switch with a hybrid type of contact, in which the movable electrode of the structure – the metal membrane is part of the microwave signal line of the coplanar waveguide. The switch design is characterized by a high capacitance ratio and low contact resistance. The zig-zag elastic suspension is used to reduce the value of the pull-down voltage – 2 V and the switching time ∼ 7 us. The central resonant frequency of the switch is 3.8 GHz. In this case, in the open state, the value of the insertion loss is not more than -0.2 dB and the isolation value in the close state is not less than -55 dB. The effective frequency range is the S-band, as well as the C-, X- and Ku-band, in which the isolation value is at least -30 dB. The presented inline RF MEMS switch is suitable for use in various types of ground and satellite communications, in particular for devices and systems of 5G mobile networks.