Showing papers on "Coplanar waveguide published in 2020"

Very-Low-Profile Grounded Coplanar Waveguide-Fed Dual-Band WLAN Slot Antenna for On-Body Antenna Application

Abstract: A very-low-profile grounded coplanar waveguide (GCPW)-fed slot antenna with an antenna thickness of 0.8 mm (about 0.0064λ at 2.4 GHz) and a compact size of 15 mm × 40 mm (about 0.12λ × 0.32λ at 2400 MHz) for 2.4/5.8 GHz dual-band wireless local area network on-body antenna application is presented. The GCPW slot antenna consists of a top ground with the GCPW feedline and radiating slot embedded thereon and a bottom ground spaced 0.8 mm to the top ground. The radiating slot is an asymmetric T-shaped slot having a longer slot path for 2400∼2500 MHz band and a shorter slot path for 5725∼5875 MHz band. It is convenient to tune the dual-band operation by adjusting the lengths of the longer and shorter slot paths, respectively. Additionally, owing to the presence of the bottom ground, the GCPW slot antenna has decreased backward radiation. This causes the antenna's impedance matching to be very slightly varied when it is in the proximity of a human body.

Compact Size and High Gain of CPW-Fed UWB Strawberry Artistic Shaped Printed Monopole Antennas Using FSS Single Layer Reflector

Abstract: This study proposed the use of coplanar waveguide Ultrawide-band strawberry artistic shaped printed monopole (SAPM) antenna with a single-layer frequency selective surface (FSS) as the metallic plate to improve the gain of antenna application. The intersection of six cylinders is used to structure the strawberry artistic shaped radiating element, which leads to enhancing the antenna bandwidth. The proposed FSS reflectors used a $10\times10$ array with the unit cell of 6mm $\times6$ mm in introducing a center-operating frequency. This study used the FR4 substrate with coplanar waveguide (CPW) fed to print the proposed antenna, which provided a wide impedance bandwidth of 8.85 GHz (3.05–11.9GHz) that covers the licensed Ultrawide-band. The proposed FSS transmitted a stop-band transmission coefficient, which is below −10 dB with the linear reflection phase over the bandwidth in the range from 3.05 GHz to 11.9 GHz. The UWB SAPM antenna with FSS reflector showed an improvement from 1.65 dB to 7.87 dB in the lower band and 6.3 dB to 9.68 dB in the upper band with an enhancement of 6.22 dB. The gain value is enhanced by the gaping between the antenna and FSS, which has an approximately constant gain response through the band, the gain is sustained among 7.87 dB to 9.68 dB. The total dimension of the antenna is 61mm $\times 61$ mm $\times 1.6$ mm. The proposed antenna structure provides the directional and balanced far-field pattern, which is suitable for Ultrawide-band (UWB) applications and ground-penetrating radar (GPR) applications.

A Novel Design Approach for Compact Wearable Antennas Based on Metasurfaces

Abstract: This paper presents a novel approach to design compact wearable antennas based on metasurfaces. The behavior of compact metasurfaces is modeled with a composite right-left handed transmission line (CRLH TL). By controlling the dispersion curve, the resonant modes of the compact metasurface can be tuned efficiently. A printed coplanar waveguide (CPW) monopole antenna is used as the feed structure to excite the compact metasurface, which will result in a low profile antenna with low backward radiation. Following this approach, two compact antennas are designed for wearable applications. The first antenna is designed to operate at its first negative mode (−1 mode), which can realize miniaturization, but maintain the broadside radiation as for a normal microstrip antenna. The proposed prototype resonates around 2.65 GHz, with a matching bandwidth of 300 MHz. The total dimensions of the antenna are 39.4 × 33.4 mm2 (0.1 λ02), and its maximum gain is 2.99 dBi. The second antenna targets dual-band operation at 2.45 and 3.65 GHz. A pair of symmetric modes (±1 modes) are used to generate similar radiation patterns in these two bands. The size of the antenna is 55.79 × 52.25 mm2 (0.2 λ02), and the maximum gains are 4.25 and 7.35 dBi in the two bands, respectively. Furthermore, the performance of the antennas is analyzed on the human body. The results show that the proposed antennas are promising candidates for Wireless Body Area Networks (WBAN).

Low-Profile Wideband Conjoined Open-Slot Antennas Fed by Grounded Coplanar Waveguides for $4\times4\,\,5$ G MIMO Operation

Abstract: Four grounded coplanar waveguide (GCPW)-fed open-slot antennas conjoined into a cross shape with a central circular slot are presented for $4\times4$ fifth-generation (5G) multi-input multi-output (MIMO) operation in 3.3–4.2 GHz. The four conjoined slot antennas have a 1 mm low profile (about $0.01\lambda $ at 3.3 GHz) and a compact size of 42 mm $\times42$ mm (about $0.46\lambda \times 0.46\lambda $ at 3.3 GHz) to provide four wide operating bands (about 24% centered at 3.75 GHz) with antenna efficiency better than 40%. The conjoined circular slot leads to enhanced operating bandwidth of the four slot antennas and good decoupling thereof. Owing to the 1 mm low profile, the conjoined slot antennas are promising to be integrated within the dielectric back cover of the 5G terminal device, thereby decreasing the antennas’ volume inside the device. Details of the GCPW-fed conjoined slot antennas for 5G-MIMO operation are presented.

Comparison of dielectric loss in titanium nitride and aluminum superconducting resonators

Abstract: Lossy dielectrics are a significant source of decoherence in superconducting quantum circuits. In this report, we model and compare the dielectric loss in bulk and interfacial dielectrics in titanium nitride (TiN) and aluminum (Al) superconducting coplanar waveguide resonators. We fabricate isotropically trenched resonators to produce a series of device geometries that accentuate a specific dielectric region's contribution to the resonator quality factor. While each dielectric region contributes significantly to loss in TiN devices, the metal–air interface dominates the loss in the Al devices. Furthermore, we evaluate the quality factor of each TiN resonator geometry with and without a post-process hydrofluoric etch and find that it reduced losses from the substrate–air interface, thereby improving the quality factor.

Resonant Tunneling Diode Terahertz Sources With up to 1 mW Output Power in the J -Band

Abstract: Terahertz (THz) oscillators based on resonant tunneling diodes (RTDs) have relatively low output power, tens to hundreds of microwatts. The conventional designs employ submicron-sized RTDs to reduce the device self-capacitance and, as a result, realize higher oscillation frequencies. However, reducing the RTD device size leads to lower output power. In this article, we present RTD oscillators that can employ one or two RTD devices of relatively large size, 9–25 μm2, for high power and, at the same time, can oscillate at THz frequencies. This is achieved through low resonating inductances realized by microstrip or coplanar waveguide transmission line short stubs with low characteristic impedances ( Z 0), which have lower inductance values per unit length and so compensate the increase of the self-capacitance of large area RTD devices. Thus, fabrication using only photolithography is possible. It is also shown that device sizing, which is limited only by bias stability considerations, does not limit device bandwidth. Further, we report a new way to estimate the RTD oscillator output power with frequency. A series of oscillators with oscillation frequencies in the 245–309 GHz range and output powers from 0.1 to 1 mW have been demonstrated showing the feasibility of the proposed approach.

Enhanced-Performance Circularly Polarized MIMO Antenna With Polarization/Pattern Diversity

Abstract: Design of a compact wideband circularly polarized (CP) multiple-input multiple-output (MIMO) antenna with polarization diversity is proposed and characterized for off-body communication. The antenna is based on a simple coplanar waveguide (CPW)-fed monopole extension of the microstrip line. The orthogonal field components required by CP are induced using a simply modified right/left side ground plane. In particular, a stub extending from the ground plane along the length of the microstrip line generates the vertical component, whereas the current along the width of the ground plane contributes to the horizontal components. To obtain a unidirectional radiation pattern in the off-body direction and to reduce the sensitivity to the human body loading effects, a flat reflector printed on a high permittivity flexible substrate is applied. The simple topology of the antenna can be described by a few adjustable parameters, which facilitates its EM design closure. Prior to the experimental validation in the free space and on the body, the antenna is optimized at the full-wave level of description for all major performance figures. The overall footprint of the antenna radiator is only $L_{s}\,\,\times $ $W_{s} =0.24\lambda _{0} \times 0.64\,\,\lambda _{0} = 0.15\,\,\lambda _{0}^{2}$ . The proposed MIMO antenna features $\vert S_{11}\vert \le -10$ dB, average isolation $\vert S_{21}\vert \le -22$ dB, and axial ratio (AR) ≤3 dB from 5.2 GHz to 6.3 GHz with 100% bandwidth overlap between the impedance and axial ratio bandwidths. The envelope correlation coefficient (ECC) is less than 0.004 with the maximum diversity gain (DG) of approximately 9.99 dB. Moreover, the antenna maintains a high efficiency of up to 90% when loaded on the body, and a low specific absorption rate (SAR).

Patch Antenna and Antenna Array on Multilayer High-Frequency PCB for D-Band

Abstract: This paper presents the design, manufacturing, and characterization of a wide-band cavity-backed aperture-coupled patch antenna and a 16-element antenna array on multilayer printed circuit board (PCB) targeted for D-band applications Microstrip line and grounded coplanar waveguide (GCPW) transmission lines are also designed and tested to investigate line losses at D-band The test structures are manufactured using printed circuit board technology with semi-additive processing (mSAP) of conductors on a multilayered substrate The measurement results indicate an insertion loss of 19 dB/cm for the microstrip line and 18 dB/cm for the coplanar waveguide at 150 GHz The measured maximum gains for single antenna and 16-element array are respectively 7 dBi and 14 dBi at 143 GHz The measured antenna input matching bandwidth is 20 GHz The results show the viability of advanced printed circuit technology for D-band transmission lines, antennas, and antenna arrays

Millimeter-Wave Multibeam Antenna Based on Folded C-Type SIW

Abstract: A millimeter-wave (mm-wave) multibeam array antenna based on folded C-type substrate integrated waveguide (FCSIW) is presented for the first time. The design steps for its two main elements are described, namely an FCSIW Butler matrix (BM) and an FCSIW single-branch slot array antenna. Both of them exhibit a significant miniaturization in comparison with their substrate integrated waveguide (SIW) counterparts, leading to 40% and 33.2% reduction in occupied surface for the BM and the whole multibeam array antenna while maintaining similar performances, respectively. In addition, an optimized transition connection structure from ground coplanar waveguide (GCPW) to FCSIW is designed to facilitate the measurement of the multibeam array antenna. Finally, the FCSIW multibeam array antenna is optimized, manufactured, and measured, which can help verify the feasibility of FCSIW for the miniaturized multibeam array antenna.

Gold Coplanar Waveguide Resonator Integrated With a Microfluidic Channel for Aqueous Dielectric Detection

Abstract: This work presents the development of a coplanar waveguide based split ring resonator, integrated with a microfluidic channel suitable for liquid sensing applications. The sensor was fabricated via photolithography on a 0.5 mm borosilicate glass substrate with patterned gold. The microfluidic channel was aligned with the sensing area and bonded to the substrate to ensure consistent liquid volume ( $0.784~\mu \text{L}$ ) over the sensing region. The microwave sensor was $1.5\times 3$ cm2 and had a resonant frequency between 19.3 and 19.4 GHz, offering the advantage of measuring extremely small sample volumes. The performance of the sensor was validated through simulations and a series of experiments using a $\vert \text{Z}\vert $ -probe station. The sensor demonstrated a resonant amplitude sensitivity of -0.085 dB/vol.% for isopropyl alcohol in water (0-100 vol.%), 0.00023 dB/[mg/dL] for various glucose concentrations (50-1200 mg/dL), and 0.00056 dB/[mg/dL] for NaCl in water (50-1200 mg/dL, with equivalent Na+ 9 - 226 mEq/L solutions); measured under room ambient conditions (24 ± 1°C and RH: 36 ± 1 %).

Broadband 300-GHz Power Amplifier MMICs in InGaAs mHEMT Technology

Abstract: In this article, we report on compact solid-state power amplifier (SSPA) millimeter-wave monolithic integrated circuits (MMICs) covering the 280–330-GHz frequency range. The technology used is a 35-nm gate-length InGaAs metamorphic high-electron-mobility transistor (mHEMT) technology. Two power amplifier MMICs are reported, based on a compact unit amplifier cell, which is parallelized two times using two different Wilkinson power combiners. The Wilkinson combiners are designed using elevated coplanar waveguide and air-bridge thin-film transmission lines in order to implement low-loss 70-Ω lines in the back-end-of-line of this InGaAs mHEMT technology. The five-stage SSPA MMICs achieve a measured small-signal gain around 20 dB over the 280–335-GHz frequency band. State-of-the-art output power performance is reported, achieving at least 13 dBm over the 286–310-GHz frequency band, with a peak output power of 13.7 dBm (23.4 mW) at 300 GHz. The PA MMICs are designed for a reduced chip width while maximizing the total gate width of 512 μm in the output stage, using a compact topology based on cascode and common-source devices, improving the output power per required chip width significantly.

Compact quasi-elliptical-self-complementary four-port super-wideband MIMO antenna with dual band elimination characteristics

Abstract: In this paper, a compact coplanar waveguide (CPW)-fed quasi-elliptical-self-complementary antenna (QESCA) exhibiting super-wideband (SWB) characteristics with dual-band notches for four-port multiple-input-multiple-output (MIMO) systems is presented. In order to achieve better inter-element isolation and polarization diversity, the four radiating elements of the MIMO antenna are placed orthogonal to each other. Each MIMO antenna element has an elliptical shape conductor patch and a slot, which is a complement of similar shape, both present on the same side of the substrate. At each port, the proposed antenna shows excellent SWB characteristics (1.25–40 GHz), providing a bandwidth ratio of 32:1. Further, two independent slits are loaded on each antenna element to reject Wi-MAX (3.5 GHz) and WLAN (5.5 GHz) bands from SWB. Inter-element isolation of more than 18 dB up to 15 GHz and over 25 dB in the higher frequency range is obtained. Measured parameters of the fabricated MIMO antenna prototype are in good agreement with the simulated results.

Metamaterial Cell-Based Superstrate towards Bandwidth and Gain Enhancement of Quad-Band CPW-Fed Antenna for Wireless Applications

Abstract: A multiband coplanar waveguide (CPW)-fed antenna loaded with metamaterial unit cell for GSM900, WLAN, LTE-A, and 5G Wi-Fi applications is presented in this paper. The proposed metamaterial structure is a combination of various symmetric split-ring resonators (SSRR) and its characteristics were investigated for two major axes directions at (x and y-axis) wave propagation through the material. For x-axis wave propagation, it indicates a wide range of negative refractive index in the frequency span of 2–8.5 GHz. For y-axis wave propagation, it shows more than 2 GHz bandwidth of near-zero refractive index (NZRI) property. Two categories of the proposed metamaterial plane were applied to enhance the bandwidth and gain. The measured reflection coefficient (S11) demonstrated significant bandwidths increase at the upper bands by 4.92–6.49 GHz and 3.251–4.324 GHz, considered as a rise of 71.4% and 168%, respectively, against the proposed antenna without using metamaterial. Besides being high bandwidth achieving, the proposed antenna radiates bi-directionally with 95% as the maximum radiation efficiency. Moreover, the maximum measured gain reaches 6.74 dBi by a 92.57% improvement compared with the antenna without using metamaterial. The simulation and measurement results of the proposed antenna show good agreement.

A Flexible High-Selectivity Single-Layer Coplanar Waveguide Bandpass Filter Using Interdigital Spoof Surface Plasmon Polaritons of Bow-Tie Cells

Abstract: In this article, a flexible high-selectivity single-layer coplanar waveguide (CPW) bandpass filter using interdigital spoof surface plasmon polaritons (SSPP) of bow-tie cells is proposed, simulated, and fabricated. The low and high cut-off frequency can be adjusted independently, which is one of the characteristics of the presented bandpass filter. The SSPP of bow-tie cells is used to adjust the high cut-off frequency, while the interdigital coupling structure of the SSPP is designed to adjust the lower one. The proposed filter also has advantages of single-layer structure and high selectivity. Simulated results of the proposed filter show a theoretical 3-dB bandwidth from 2.28 to 5.12 GHz (about 76.8%) with high selectivity ( $\vert S_{11}\vert dB and −0.4 dB $> \vert S_{21}\vert > -1.1$ dB in the passband), and measured results agree well with simulated ones. Since the filter in this article is designed based on the flexible printed circuit (FPC) board, the circuit can be tested in bent, folded, and even twisted states, and these measured results are all basically consistent with the test result of the flat state circuit. This characteristic can greatly reduce the size of the filter and increase the flexibility of the circuit application.

Design of Quad-Port MIMO/Diversity Antenna with Triple-Band Elimination Characteristics for Super-Wideband Applications.

Abstract: A compact, low-profile, coplanar waveguide (CPW)-fed quad-port multiple-input-multiple-output (MIMO)/diversity antenna with triple band-notched (Wi-MAX, WLAN, and X-band) characteristics is proposed for super-wideband (SWB) applications. The proposed design contains four similar truncated-semi-elliptical-self-complementary (TSESC) radiating patches, which are excited through tapered CPW feed lines. A complementary slot matching the radiating patch is introduced in the ground plane of the truncated semi-elliptical antenna element to obtain SWB. The designed MIMO/diversity antenna displays a bandwidth ratio of 31:1 and impedance bandwidth (|S11| ≤ - 10 dB) of 1.3-40 GHz. In addition, a complementary split-ring resonator (CSRR) is implanted in the resonating patch to eliminate WLAN (5.5 GHz) and X-band (8.5 GHz) signals from SWB. Further, an L-shaped slit is used to remove Wi-MAX (3.5 GHz) band interferences. The MIMO antenna prototype is fabricated, and a good agreement is achieved between the simulated and experimental outcomes.

Ultra-Miniature Circularly Polarized CPW-Fed Implantable Antenna Design and its Validation for Biotelemetry Applications.

Abstract: The paper presents a coplanar waveguide (CPW)-fed ultra-miniaturized patch antenna operating in Industrial, Scientific and Medical (ISM) band (2.4–2.5 GHz) for biotelemetry applications. The proposed antenna structure is circular in shape and its ground plane is loaded with a pair of slots for obtaining circular polarization. In the proposed design, asymmetric square slots generate phase condition for right-hand circularly polarized (RHCP) radiation. And, by merely changing the position of the slots, either RHCP or left-hand circularly polarized (LHCP) radiation can be excited. In the proposed design, a meandered central strip is used for miniaturization. The simulations of the proposed antenna are carried out using Ansys HFSS software with a single-layer and multilayer human tissue models. The antenna shows good performance for different tissue properties owing to its wide axial ratio bandwidth and impedance bandwidth. The antenna is fabricated and measurements are carried out in skin mimicking phantom and pork. Simulated and measured performances of the antenna are in close agreement. The power link budget is also calculated using an exterior circularly polarized (CP) receiving antenna.

A Grounded Coplanar Waveguide-Based Slotted Inverted Delta-Shaped Wideband Antenna for Microwave Head Imaging

Abstract: A wideband grounded coplanar waveguide (GCPW) based patch antenna for head imaging is discussed in this paper. The proposed antenna is integrated with a slotted inverted delta-shaped main radiating patch, coplanar waveguide elements, and slotted partial ground. The prime objective of usages of coplanar waveguide elements is enhancing antenna effectiveness. In the prototype, examined different categories of slots in the ground and particularly rectangular and elliptical-shaped slots are used to improve the radiation directivity, gain, and efficiency. The optimized dimension of the antenna is $50\times 44\times 1.524$ mm3 by using the Rogers RO4350B substrate. The measured and simulated results demonstrate that the proposed prototype has a bandwidth of 2.01 GHz (1.70–3.71 GHz) with nearly directional radiation characteristics. The highest gain of the prototype is 5.65 dBi, and the maximum 93% radiation efficiency over the frequency band. The antenna has a lower group delay, higher fidelity factor (>95%), which are significant factors for microwave head imaging. Various design structures are performed to achieve the most satisfactory result. The proposed prototype is designed and analyzed by 3D CST 2019 simulator software. Later, the antenna is fabricated and measured to examine the performance. Thereafter, a single antenna and twelve-antennas array element are configured and placed surrounding the 3D realistic shaped Hugo head model to validate the effectiveness of the single antenna as well as the designed antennas array. The antenna has satisfactory field penetration into the human head tissues with a safe SAR (specific absorption rate). Less than 0.00233 W/kg SAR is attained over the operating frequency range, which is lower than the reported antennas. The Iteratively Corrected Delay Multiply and Sum (IC-DMAS) imaging algorithm will be applied for imaging purposes. The investigation through the literature of the statistical and measured data evident that the proposed antenna is apposite for the wideband microwave head imaging applications.

A Flexible Microwave Sensor Based on Complementary Spiral Resonator for Material Dielectric Characterization

Abstract: In this paper, a flexible microwave sensor for material dielectric characterization is presented. The sensor is composed of a two-turn complementary spiral resonator (CSR) in coplanar waveguide (CPW) technology developed on a flexible polyethylene terephthalate (PET) substrate. The sensing principle is based on the measured transmission coefficient of the designed structure, where the resonant frequency and its magnitude are in function of the dielectric properties of loaded materials under test (MUTs). A prototype of the proposed sensor is fabricated and experimentally validated by extracting the dielectric constant and loss tangent of the reference samples loaded above the region of the CSR. Specially, due to the flexibility, the fabricated sensor can be conformally attached to the palm of a dexterous robotic hand to function as robotic electronic skin for material dielectric characterization, more specifically, to obtain dielectric properties of the objects grasped by the dexterous robotic hand. Moreover, the sensing functionality of the sensor structure under different bending levels is validated by calculating the dielectric property of loaded objects with non-planar surfaces.

Wide-Angle Frequency Beam Scanning Antenna Based on the Higher-Order Modes of Spoof Surface Plasmon Polariton

Abstract: A wide-angle frequency beam scanning antenna based on spoof surface plasmon polaritons (SSPPs) is proposed for planar-integrated communication circuits. The SSPP-based antenna is constructed by hole arrays etched on the standard $50~\Omega $ coplanar waveguide, which can achieve ultrawide bandwidth and wide-angle beam scanning from backward direction to forward direction as the frequency changes. The radiation mechanisms of the SSPP-based antenna are based on the higher-order modes of the structure, which have been analyzed by the dispersion curves and electric field distributions. The overall width of the proposed SSPP-based antenna is only $0.95\lambda _{0}$ (with $\lambda _{0}$ being the wavelength of the lowest working frequency). The simulated results show that the proposed frequency beam scanning antenna achieves a wide scanning angle of 129° over a frequency range from 11.7 to 50 GHz (for $\vert S_{11}\vert dB) with an average gain level of 12.38 dBi. The good agreements between the simulated and measured results validate the proposed design.

Design and Implementation of Quad-Element Super-Wideband MIMO Antenna for IoT Applications

Abstract: In this article, a low-profile, compact, quad-port super-wideband (SWB) multiple-input–multiple-output (MIMO) antenna is presented for the internet of things (IoT) applications. The proposed antenna comprises four identical sickle-shaped resonating elements, which are excited by tapered coplanar waveguide (CPW) feed lines. The antenna elements are arranged in rotational symmetry (mutually orthogonal to each other) to achieve high port isolation. A complementary slot, which matches the sickle-shaped radiator, is etched from the ground of the proposed monopole antenna element to achieve massive bandwidth. The MIMO antenna possesses a resonating bandwidth ( $\vert S_{11}\vert \le -10$ dB) of 1.3–40 GHz and a bandwidth ratio of 31:1. In addition, an L-shaped slit and a complementary split-ring resonator (CSRR) are introduced in the sickle-shaped radiator to reject Bluetooth (2.4 GHz), WLAN (5.5 GHz), and downlink of X-band satellite communication (7.5 GHz) signals from the SWB. The proposed MIMO antenna is fabricated and experimental results are found in agreement with the simulated results.

Gain Enhancement of Millimeter-Wave On-Chip Antenna Through an Additively Manufactured Functional Package

Abstract: The antenna-on-chip (AoC) presents an excellent solution for applications requiring higher integration levels and lower cost; however, its radiation performance is poor due to the inherent lossy Si substrate in conventional complementary metal–oxide–semiconductor (CMOS) processes. It is well known that every chip requires a package to protect it from the environment; however, this package does not provide any functionality, despite adding to the cost and required space. In this article, we propose a functional package that has been designed to enhance the gain of the AoC. A 71 GHz coplanar waveguide (CPW)-fed on-chip monopole antenna, driven by a voltage-controlled oscillator (VCO) and frequency doubler, was realized in the standard 0.18 $\mu \text{m}$ CMOS technology. As a first step to enhance its gain, the AoC was designed on top of an artificial magnetic conductor (AMC) surface. Further gain enhancement was achieved by transforming the chip package into a combination of a superstrate layer and a Fresnel lens, qualifying this as a system-on-package (SoP). The package has been realized through additive manufacturing to maintain the low-cost aspect. Overall, the measured gain of the packaged AoC is 6.8 dBi, which has been enhanced by ~20 dBs compared to the unpackaged antenna without an AMC layer.

Phononic loss in superconducting resonators on piezoelectric substrates

Abstract: We numerically and experimentally investigate the phononic loss for superconducting resonators fabricated on a piezoelectric substrate. With the help of finite element method simulations, we calculate the energy loss due to electromechanical conversion into bulk and surface acoustic waves. This sets an upper limit for the resonator internal quality factor Q i. To validate the simulation, we fabricate quarter wavelength coplanar waveguide resonators on GaAs and measure Q i as function of frequency, power and temperature. We observe a linear increase of Q i with frequency, as predicted by the simulations for a constant electromechanical coupling. Additionally, Q i shows a weak power dependence and a negligible temperature dependence around 10 mK, excluding two level systems and non-equilibrium quasiparticles as the main source of losses at that temperature.

A High Efficiency Band-Pass Filter Based on CPW and Quasi-Spoof Surface Plasmon Polaritons

Abstract: A high efficiency and compact band-pass filter based on coplanar waveguide (CPW) is investigated in this paper, which lower and upper cut-off frequencies of the proposed filter can be tuned independently. In the proposed design, interdigital structure is used to filter the low frequency wave and a quasi-spoof surface plasmon polaritons (Q-SSPPs) structure is designed for tuning the higher cut-off frequency. The proposed Q-SSPPs structure contains only one cross-shaped element and keeps the similar properties of periodic SSPPs structure. The operating principle of the proposed design is explained by field distribution, dispersion curves, and equivalent circuits. The studies of vital parametric are carried out for better understanding the influences of the concerning parameters on the tunability. The simulated results indicate that the proposed design can obtain a wide bandwidth from 8.8 GHz to 17 GHz (about 63.6%) with high transmission efficiency (IS 11 I <; -15 dB and IS 21 I > -0.2 dB). A prototype of the proposed design is fabricated and the measured results show good agreement with the simulated ones.

Coupling Rydberg Atoms to Microwave Fields in a Superconducting Coplanar Waveguide Resonator.

Abstract: Rydberg helium atoms traveling in pulsed supersonic beams have been coupled to microwave fields in a superconducting coplanar waveguide (CPW) resonator. The atoms were initially prepared in the 1 s 55 s 3 S 1 Rydberg level by two-color two-photon laser excitation from the metastable 1 s 2 s 3 S 1 level. Two-photon microwave transitions between the 1 s 55 s 3 S 1 and 1 s 56 s 3 S 1 levels were then driven by the 19.556 GHz third-harmonic microwave field in a quarter-wave CPW resonator. This superconducting microwave resonator was fabricated from niobium nitride on a silicon substrate and operated at temperatures between 3.65 and 4.30 K. The populations of the Rydberg levels in the experiments were determined by state-selective pulsed electric field ionization. The coherence of the atom-resonator coupling was studied by time-domain measurements of Rabi oscillations.

Miniature Slotted Semi-Circular Dual-Band Antenna for WiMAX and WLAN Applications

Abstract: In this paper, a new approach is presented for designing a miniaturized microstrip patch antenna (MPA) for dual-band applications. The proposed MPA consists of a semi-circular patch radiator fed by a 50-Ω coplanar waveguide (CPW) structure with a tapered-ground plane for enhancing impedance bandwidth over the dual-band. By inserting a folded U-shaped slot into the semi-circular patch, the proposed antenna introduces an additional higher-order mode but does not modify the resonance frequency of the lower-order mode of the patch, yielding the desired dual-band response. For antenna miniaturization, the circular-shaped radiator of the reference antenna (RA) was converted into a semi-circular radiating patch. Agreement between CST and HFSS simulated results led us to manufacture a prototype of the designed antenna on one side of an inexpensive FR-4 substrate with an overall dimension of 17 × 18 × 0.8 mm3. The measured result in terms of reflection coefficient S11 confirms that the antenna operates in both 3.5 GHz (3.4–3.7 GHz) and 5.8 GHz (5.725–5.875 GHz) bands suitable for use in WiMAX and WLAN applications, respectively. Moreover, besides an area reduction of 32% compared with the RA counterpart, the proposed antenna has other features, a simple geometry, and is easy to manufacture in comparison with previously reported antenna structures.

Design of Smartwatch Integrated Antenna With Polarization Diversity

Abstract: A design of smartwatch integrated antenna with polarization diversity is proposed. An annular ring is integrated in the framework of smartwatch, and excited by two ports. One port is fed by a coplanar waveguide (CPW) line loaded with a T-shaped matching network, and the other is fed by a coplanar strip line (CPS). The overall model of the proposed antenna has a cylindrical shape with 38 mm diameter and 7.5 mm thickness. A metallic plate is located at the backside of the antenna to mimic the shell of smartwatch. The prototype is fabricated and measured, and the measured results agree well with the numerical ones. The two ports have orthometric radiation patterns and can cover the 2.4 GHz wireless local area network (WLAN) band. The gain of the antenna is higher than 3.2 dBi in free space. The proposed antenna is also analyzed with a cubic tissue model and a wrist model in different distances between the proposed antenna and human models. The performances on body scenarios are also acceptable. The values of specific absorption rate (SAR) in the cubic tissue model and wrist model are below the limitations set by both the Federal Communication Commission (FCC) and the European Telecommunication Standards Institute (ETSI). Envelope correlation coefficient (ECC) shows proposed antenna can be used in multiple input multiple output (MIMO) applications. The influence of battery and printed circuits board assembly (PCBA) on S parameters is obvious, and gain and radiation efficiency are not much affected.

Asymmetric CPW-fed electrically small metamaterial- inspired wideband antenna for 3.3/3.5/5.5 GHz WiMAX and 5.2/5.8 GHz WLAN applications

Abstract: In this work, a new concept is introduced to enhance the bandwidth of metamaterial (MTM) inspired antenna. The MTM inspired antenna mainly comprises a single split-ring resonator and a hexagonal-shaped closed ring resonator with asymmetric coplanar waveguide feed, which leads to antenna compactness. The physical dimension of the intended antenna is 17 mm × 20 mm × 1.6 mm. Due to MTM loading, the antenna achieves more compactness with ka = 0.87

An Ultra-Wideband Rectangular Dielectric Resonator Antenna With MIMO Configuration

Abstract: A Coplanar waveguide (CPW) fed multi-permittivity and stair shaped dual rectangular dielectric resonator antenna (RDRA) has been designed for ultra-wideband (UWB) applications in multiple-input multiple-output (MIMO) configuration. Isolation improvement has been obtained by means of modified CPW feeding and a metallic diagonal stub in the proposed structure. The simulated results have been validated by prototype designing and performing measurements. The electrical size of the proposed antenna configuration is $1.12\lambda _{0}\times 1.12\lambda _{0}\times 0.25\lambda _{0}$ . The measured input impedance bandwidth of the antenna is 153.6% (1.6-12.2 GHz) with a minimum of 25 dB isolation between the radiators in the operating band. Measured results illustrate the satisfactory performance of proposed UWB MIMO antenna with a low envelope correlation coefficient and low mutual coupling throughout the desired frequency range.

Direct-Write Dispenser Printing for Rapid Antenna Prototyping on Thin Flexible Substrates

Abstract: Rapid prototyping of antennas is crucial to validation of simulation models when designing conformal antennas on unusual substrates such as polymers and textiles. This paper presents direct-write dispenser printing, using a commercial Printed Circuit Board (PCB) printer, as a simple mean of prototyping planar antennas on ultra-thin (25 $\mu$ m) flexible Polyimide substrates. Two Coplanar Waveguide (CPW) monopole antennas have been designed for the 2.4 GHz band and fabricated using dispenser printing and standard photolithography. The impedance bandwidth and gain of both antennas has been compared and the printed prototype was found to match the performance of the etched antenna within a 2.6% and 2.3% margin respectively, as well as matching the full-wave 3D simulation of the connectorized antennas. Based on the measured performance of the printed antenna, the potential of utilising commercial dispenser printers to prototype and manufacture low-volume antennas for low-cost unobtrusive Internet of Things applications is demonstrated.