Design of Flexible 3.2 GHz Rectangular Microstrip Patch Antenna for S-Band Communication

This paper presents the design, simulation, realization and analysis of flexible microstrip patch antenna for S-band applications. The proposed design also adopts the conformal structure by utilizing flexible substrate. Conformal or flexible structure allows the antenna to fit with any specified shape as desired. The antenna patch dimensions is 43 mm × 25 mm without SMA connector. The patch is etched on the flexible dielectric substrate, pyralux FR 9111, with a relative dielectric constant of εr = 3 and the thickness of substrate, h = 0.025 mm. The antenna is designed to resonate at 3.2 GHz. The return loss (RL) of the simulation is -35.80 dB at the center frequency of 3.2 GHz. The fabricated antenna prototype was measured at different bending angles scenarios including 0º, 30º, 60º, and 90º. The measurement of antenna prototype shows that the center frequency is shifted to the higher frequency of 3.29 GHz, compared to the simulation result. Among these scenarios, measurement at bending angle of 90º gives the best performance with RL = - 31.38 dB at 3.29 GHz, the bandwidth is 80 MHz, and the impedance ZA = 48.36 + j2.04 Ω. Despite a slight differences from simulation results, the designed antenna still performs well as expected.

A Novel Dual-Band “C+O” Structure Antenna

This article proposes a novel multiband antenna with “C + O” structure, which uses two classic circular letters and combines them. The antenna is suitable for wireless applications such as second generation (2G), third generation (3G), fourth generation (4G), WLAN, and Bluetooth. The antenna is based on the structural characteristics of the classic monopole antenna. It is a vertical quarter-wavelength antenna. The radiator of the antenna is mainly composed of letters, and the radiator is symmetrical along the feeder line. The antenna radiator is composed of “C + O” structure. The antenna uses a coplanar waveguide feeding method. After actual testing, the antenna covers two frequency bands: 1.82–2.66 GHz and 3.46–3.72 GHz. The center frequency points are 2.06 GHz and 3.68 GHz. The antenna uses FR-4 dielectric material, the relative dielectric constant of the dielectric plate is 4.4, and the actual size of the antenna is 15 × 15 × 1.6 mm³. The test and simulation have good consistency, which verifies that the proposed antenna meets the requirements of various wireless applications.

Design of a compact reconfigurable bandpass filter using interdigital capacitor, DMS slots and varactor diode for wireless RF systems

This paper proposes a new design of a reconfigurable bandpass filter based on an interdigital capacitor and varactor diode for wireless and mobile applications. The designed reconfigurable bandpass filter has been implemented on an RT 6010 substrate with a relative dielectric constant of 10.2, thickness of 1.27 mm, and loss tangent of 0.0023. In order to reduce the filter size, the defected microstrip structure (DMS) is used due to its easy design, high compactness, high quality factor and easy integration with other RF devices. The suggested reconfigurable filter has a simple structure with a very attractive compact size of 4.7 × 8.4 mm2, low insertion loss than -1 dB, and tuning range (2–2.6 GHz).

Model of Е-polarized wave propagation in a multilayer dielectric structure

This paper addresses the determination of the dielectric constant of multilayer dielectric structures by radiowave interferometry. In the general case, in interferometry measurements to one measured value of the reflection coefficient there may correspond an infinity of dielectric constants. This ambiguity may be resolved by first determining the effect of different parameters of the probing electromagnetic wave on the reflection coefficient. In particular, it is important to have a preliminary estimate of the effect of the incidence angle and the polarization on the range of variation of the reflection coefficient with the variation of one of the structure parameters. This paper considers the case where a plane E-polarized electromagnetic wave, i.e. a wave whose magnetic field is perpendicular to the incidence plane, is incident on a multilayer dielectric structure. The aim of this work is to develop a model of the propagation of an E-polarized electromagnetic wave through a multilayer dielectric structure at an arbitrary incidence angle and to determine the range of variation of the reflection coefficient with the variation of the dielectric constants of the layers. The paper presents a model of the propagation of an E-polarized electromagnetic wave in a two-layer dielectric structure. A metal base, which is an ideal conductor, underlies the structure. The electromagnetic wave is incident from the air at an arbitrary incidence angle. Based on the model, a method is proposed for measuring the relative dielectric constant and the dielectric loss tangent. It is shown that at a normal incidence the reflection coefficient magnitude is the same both for H- and E-polarization. Because of this, determining the relative dielectric constant and the loss tangent from the measured reflection coefficient magnitude calls for measurements not only at a normal incidence, but also at an oblique incidence, at which the reflection coefficient magnitudes will be different for H- and E-polarization.

A new design of stepped antenna loaded metamaterial for RFID applications

Radio frequency identification is being overloaded with data information, making wideband band antennas very appealing. In this paper, we present a new design of dual band antenna for RFID reader applications operating at 2.45Gz and 5.8GHz with an average gain of 1.16dB at the lower frequency band and 3.2dB at the higher frequency band. The antenna is designed on an FR-4 substrate having a relative dielectric constant of 4.4 and loss tangent of 0.025. The proposed antenna is simulated, designed and, optimized using CST Microwave Studio and has a small size of 32 mm x 26 mm x 1.6 mm. The antenna consists of a steeped rectangular patch antenna using a partial ground plane loaded a modified split ring resonator. The metamaterial structure was designed and optimized to operate at 2.45GHz and its effective parameters was verified using the Nicolson-Ross Weir method. The performance of the proposed antenna is confirmed by another 3D electromagnetic solver HFSS.

MULTI BAND MICRO STRIP PATCH ANTENNA FOR WIRELESS APPLICATIONS

This research paper aims to design a new shape of the microstrip patch antenna. Combining a half circular and zigzag shape of a triangular patch antenna, we selected two different shapes of microstrip patch to obtained modern shape no one mentioned it before and it’s seems like a tulip rose, so this design achieved to works for multiband. The dimensions of the proposed antenna are (38×30×1.6) mm3 applied on the dielectric substrate FR-4, which has a relative dielectric constant of (εr=4.3) and loss tangent (tanδ=0.002). Both patch and ground are copper material with a thickness (t=0.035 mm). So four-band are achieved (5.1612-5.3874) GHz, (8.8729-10.067) GHz, (10.476-11.091) GHz, and (13.819-30) GHz. The return loss (S11) are (-20.784) dB, (-30.532) dB, (-19.246) dB and (-29.789) dB respectively. The antenna is printed by using FR-4 substrate and simulated by CST-Microwave studio software. This antenna works for various wireless applications such as Wi-FI, C band, X band, Ku band, Ka-band, cellular phones, and satellite communications.

Improvement in mechanical properties in AlN-h-BN composites with high thermal conductivity

It is possible to improve the machinability of aluminum nitride-hexagonal boron nitride (AlN-h-BN) ceramics while maintaining high strength and high thermal conductivity. The composite ceramics with 0–30 wt% BN as secondary phase were prepared by hot pressed sintering, using yttrium oxide (Y2O3) as sintering aid. The phase composition, density, microstructure, mechanical properties, thermal conductivity, and dielectric properties were investigated. The sintering additives were favorable to purify the grain boundaries and improve densification, reacting with oxide impurities on the surface of raw material powder particles. The optimum BN content improved the flexural strength and fracture toughness of composite ceramics with 475 MPa and 4.86 MPa·m1/2, respectively. With increasing the amount of BN, the thermal conductivity and hardness of composites gradually decreased, but the minimum value of thermal conductivity was still 85.6 W·m−1·K−1. The relative dielectric constant and dielectric loss tangent of the samples ranged from 6.8 to 8.3 and from 2.4 × 10−3 to 6.4 × 10−3, respectively, in 22–26 GHz.

Structure, Defects and Microwave Dielectric Properties of Al-doped and Al/Nd Co-doped Ba4Nd9.33Ti18O54 Ceramics

Ba4Nd9.33Ti18-zAl4z/3O54 (BNT-A, 0 ≤ z ≤ 2) and Ba4Nd9.33+z/3Ti18-zAlzO54 (BNT-AN, 0 ≤ z ≤ 2) ceramics were prepared by solid state method, and the effects of the two doping methods on microwave dielectric properties were compared. As the doping amount z increased, the relative dielectric constant (εr) and the temperature coefficient of resonant frequency (τf) values of the ceramics decreased, and the quality factor (Q, usually expressed by Q×f, where f is the resonant frequency) of the ceramics obviously increased when z ≤ 1.5. With the same z value, the εr and Q×f values of Al/Nd co-doped ceramics are both higher than those of Al-doped ceramics. Rietveld refinement, Raman spectroscopy and thermally stimulated depolarization current (TSDC) technique were applied to clarify the relationship among the structure, defects and microwave dielectric properties. It is shown that the Q×f values of those ceramics were closely related to the strength of the A-site cation vibration and the concentration of oxygen vacancies (B). Excellent microwave dielectric properties of εr = 72.2, Q×f = 16480 GHz, and τf = +14.3 ppm/℃ were achieved in BNT-AN ceramics with z = 1.25.

Application of Amorphous Zirconium-Yttrium-Aluminum-Magnesium-Oxide Thin Film with a High Relative Dielectric Constant Prepared by Spin-Coating

Amorphous metal oxide has been a popular choice for thin film material in recent years due to its high uniformity. The dielectric layer is one of the core materials of the thin film transistor (TFT), and it affects the ability of charges storage in TFT. There is a conflict between a high relative dielectric constant and a wide band gap, so we solved this problem by using multiple metals to increase the entropy of the system. In this paper, we prepared zirconium-yttrium-aluminum-magnesium-oxide (ZYAMO) dielectric layers with a high relative dielectric constant using the solution method. The basic properties of ZYAMO films were measured by an atomic force microscope (AFM), an ultraviolet-visible spectrophotometer (UV-VIS), etc. It was observed that ZYAMO thin films had a larger optical band when the annealing temperature increased. Then, metal-insulator-metal (MIM) devices were fabricated to measure the electrical properties. We found that the leakage current density of the device is relatively lower and the ZYAMO thin film had a higher relative dielectric constant as the concentration went up. Finally, it reached a high relative dielectric constant of 56.09, while the leakage current density was no higher than 1.63 × 10−6 A/cm2@ 0.5 MV/cm at 1.0 M and 400 °C. Therefore, the amorphous ZYAMO thin films has a great application in the field of high permittivity request devices in the future.

Analysis of the Influence of Silicone Rubber Aging on the Transmission Parameters of Terahertz Waves

In this study, a method for testing the aging of silicone rubber insulators using terahertz waves in the 0.17–0.22 THz frequency band is proposed, aiming at the problem of online non-destructive testing of the aging degree of composite insulators. The relationship between the aging degree of silicone rubber composite insulators and the relative dielectric constant was studied through first-principles calculations and molecular chain scission models. In addition, the electromagnetic model of the terahertz signal incident on the silicon rubber sheet was simulated and the relationship between the aging degree of the silicon rubber and the terahertz input return loss was obtained. Eleven insulator samples with different degrees of aging were selected. In these samples, the degree of aging was calibrated according to the degree of surface deterioration and the average partial discharge voltage. The terahertz return loss measurement experiment was performed after that. Finally, the results of experiment and calculation simulation were compared and the reliability of the relationship between the aging degree of the silicone rubber insulator and the terahertz input return loss was verified.