SMA Connector Research Articles

Design and performance analysis of small-sized multiband microstrip patch antenna on custom-made biopolymer substrate

Abstract This paper presents a simple design analysis and performance evaluation of rectangular, slotted, microstrip feed patch antenna. The design processes are performed by employing the finite element method (FEM)-based commercial EM simulation software High-Frequency Structural Simulator (HFSS). The proposed multiband antenna is composed of a rectangular, slotted radiator formed with four arc slots and central square slot, reduced ground plane, and microstrip line for feeding. The patch antenna is excited through the standard 50 Ω RF transmission line, impedance-compliant SMA connector that is connected to the microstrip line. The optimal parametric dimensions from the numerical simulations are used for constructing the physical prototype on a custom-made, ceramic-filled biopolymer substrate of ε r=10.0. Based on simulation results, the experimental data are collected, analyzed, and compared; the surface current distributions on the patch, gain, and radiation patterns are critically discussed. The measured results show the impedance bandwidths for S11 less than -10 dB are 712 MHz at 0.788 GHz band, 1.38 GHz at 3.34 GHz band, and 2.46 GHz at 8.01 GHz band. The good radiation pattern performances, almost stable gain over the bands, and appreciable bandwidths recommend the antenna for operating in RFID, WiMAX, and C/X-band applications.

Planar High-Gain Circularly Polarized Element Antenna for Array Applications

This paper proposes a planar high-gain circularly polarized element antenna that can be used for array applications. The substrate-integrated waveguide (SIW) cavity is designed to support dual-resonant modes, the ${\bf TE}_{{\bf 120}}$ -like and ${\bf TE}_{{\bf 210}}$ -like modes, for the implementation of circularly polarized radiation performance. Four rectangular radiation slots and a large perturbation, introduced by inserting a metallic via-brick into the SIW cavity, are deployed to achieve a high simulated gain of 10.28 dBi at 6.65 GHz for the proposed element. As a demonstration of an array application, a $4 \times 4$ array antenna is designed using the proposed element with a compact beam-forming network. Experiments are carried out to verify the designed prototypes. The measured peak gains of the designed element and array antennas are 9.6 and 20.1 dBi, respectively, which include the loss from SMA connectors. Good agreement between simulated and measured results is obtained.

Single-feed circularly polarized stacked patch antenna with small-frequency ratio for dual-band wireless applications

A single-feed dual-band circularly polarized stacked microstrip patch antenna with a small-frequency ratio is presented. Two pair of orthogonal slits is cut on the lower circular patch for achieving circular polarization and truncated corner square patch is used as the upper parasitic element. The frequency ratio of the dual-band is 1.03. The 3 dB axial ratio bandwidth is 1.3% for the upper band and 1.1% for the lower band. Proposed structure is fabricated on the FR-4 epoxy substrate and fed by SMA connector. The measured results are in good agreement with the theoretical and simulated results. The antenna shows stable radiation characteristics in both bands of operation.

Corner truncated broadband patch antenna with circular slots

ABSTRACTIn this communication, a corner truncated broadband patch antenna with circular slots is presented. The proposed antenna is fabricated on 14 * 14 * 1.57 mm3 Rogers RT5870 substrate (εr = 2.33 and loss tangent of 0.0012) and a 50‐Ω SMA connector is used for excitation. Bandwidth enhancement has been reported due to cutting of two circular slots and truncating the corners of the square patch, which gives rise to mode splitting phenomenon and better impedance matching. Simulated results show that the impedance bandwidth (S11 < 10 dB) of the proposed antenna is 19% (10.8–13.2 GHz). Measured results are in good agreement with the simulated results. The fractional bandwidth of the proposed antenna has enhanced from 8.5 to 19% as compared to the simple patch antenna, showing an enhancement of 123%. The peak gain of the proposed antenna is 7 dB. The antenna finds application in satellite communication, radar communication, and other alleged wireless communication services. Details and comparison of the proposed antenna with simple patch antenna have been described. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:845–849, 2015

Investigation of Novel Noncontacting Measurement Method by the Design of Loop-Type Probe and Reconstruction of Radiation Modeling

Because the ICs’ application frequency and speed become higher and trends of system packaging and device under test request higher reliability, a novel technology combining noncontacting measurement method and reconstructing radiation model was proposed to solve signal deliveries in system packages or PCBs. In this study, a novel noncontacting method for the ICs’ measurements was investigated by the design of loop-type near-field probe and reconstructed the radiation model to substitute the traditional measurement methods, such as using probes and SMA connectors. A near-field probe was used to receive the coupling signal. The assessing circuit modeling could be completed by some synthesized theorems. According to the study’s results, frequency responses of reconstruction model developed by theorems, radiation measurements, and simulated by EM methods were highly curve fitting.

Comparison of Power Handling Capability of Double-strip Resonator Filters with Stripline Structure and Conventional Microstrip Line Filters

The power handling capability of a high temperature superconducting transmit filter with a double-strip resonator (DSR) was investigated by comparing the performances of such a filter with conventional microstrip-line (MSL) filter. The DSR structure consists of two coupled strips and the center pin of the SMA connector as feed line. The idea is to increase the effective film thickness to reduce the current concentration at the edges of the resonator compared with that of an MSL resonator. The two three-pole filters were designed using electromagnetic simulator. The center frequency and 3dB-bandwidth are a 5.0-GHz and a 100-MHz. The two filters were fabricated using YBa2Cu3Oy thin films on a CeO2-buffered r-Al2O3 substrate. The measured frequency responses of the filters were in reasonable agreement with the simulated ones. The measured power handling capability of the DSR filter was 3.5 dBm larger than that of the MSL filter.

Dual band inverted L‐shape monopole antenna for cellular phone applications

ABSTRACTTo mitigate the requirement of dual band cellular phone applications, inverted L‐shaped monopole antenna is proposed in this article. The proposed antenna have optimum dimensions 22 (L) × 76 (W) × 1.6 (h) mm3 and fabricated on easily available FR4 substrate with permittivity 4.4 and loss tangent is 0.02. The structure is feed to 50‐Ω microstrip line and terminated with SMA connector. The antenna covers 824–894 MHz (AMPS), 890–960 MHz (GSM) in lower frequency bands, and 2–2.5 GHz (Wi‐Fi, Bluetooth, WiMAX) in upper frequency bands. Measured VSWR is ≤2 for both dual band of frequencies. The antenna shows acceptable gain flatness from 1.5 to 3.59 dBi with good omnidirectional radiation pattern. In addition, an attempt is made to investigate the effect of L‐patch on the impedance bandwidth with extensive simulation and result are presented. The antenna offers high efficiency for both dual frequency bands and easy integration with the other microwave circuits. Its simplicity, gain flatness, and radiation patterns make it suitable for dual band cellular phone applications. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2751–2755, 2014

Bandpass Filters With Localized Temperature Compensation Dielectrics in Low-Temperature Cofired Ceramic Packages

A series of SrTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (STO) based temperature compensation dielectrics that were cofireable with the commercial DuPont 951 low-temperature cofireable ceramic (LTCC) were developed. The STO30 dielectric with 30 wt% STO showed the highest positive temperature coefficient of resonant frequency (τ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> ) that was opposite to the τ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> = -69 ppm/°C of the Dupont 951 LTCC, and was selected to design a temperature-compensated four-pole bandpass filter. The filter shows a near zero τ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> = 0.7 ppm/°C over a temperature range -20 °C to 80 °C. The variance of insertion loss of the filter over the same temperature span is 0.28 dB. The maximum-difference group delay of the filter is 37 pS. The insertion loss included two SMA connectors at 20 °C is greater than 2.45 dB. A general variational method with the transmission-line technique provided an analytical method to calculate the effective dielectric constant and the characteristic impedance of an arbitrary multilayer strip line structure. With this method, the thickness of STO30 compensation dielectric can be optimized to obtain a nearly full temperature compensation for the filter. The electromagnetic simulation results of the filter agreed well with measured data.

Stacked dual-band circularly polarized microstrip antenna with small frequency ratio

A single feed dual-band circularly polarized stacked microstrip patch antenna with a small frequency ratio is presented. The lower patch is having a pair of peripheral cuts in the circular patch with cross slot loaded at the center and truncated corner square ring is used as the parasitic patch. The frequency ratio of dual-band achieved is 1.05. The 3-dB axial ratio bandwidth is 1.4% for the upper band and 1.1% for the lower band. Proposed structure is fabricated on the FR-4 epoxy substrate and fed by SMA connector. The measured results are in good agreement with the simulated. The antenna shows stable radiation characteristics for both the operating bands. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1933–1937, 2014

A HIGH TEMPERATURE SUPERCONDUCTOR MICROWAVE FILTER WORKING IN C-BAND FOR THE SARDINIA RADIO TELESCOPE

A planar band-pass filter based on High Temperature Superconductor (HTS) has been designed for possible implementation in the cryogenic front-end of the C-band receiver for the Sardinia Radio Telescope. The band-pass filter is designed to operate at relatively high frequencies: center frequency 6.7 GHz with 30% bandwidth. Seven nominally identical filters have been fabricated to test different carrier materials and connector types aimed to keep the fabrication of the HTS filter simpler and more cost competitive. In addition to the conventional approach, silver plating, copper carriers and SMA connectors have been used. Cryogenic scattering parameter measurements show a good agreement with numerical results: the average of the transmission losses turns out to be in the range 0.15–0.25 dB depending on the prototypes, whereas the reflection coefficient is below -16 dB. The insertion loss has been also measured by using a radiometric approach based on the cold attenuator method showing consistent results with those given by the Vector Network Analyzer. Multiple cool-down measurements have been performed successfully proving the data repeatability both in short- and medium-term. Concerning alternative technical solutions, the SMA connectors and silver plating appear to be valid options whereas the copper carriers are inclined to destroy the circuit. Finally, numerical simulations and experimental measurements on a traditional copper filter operating at 20 K show that the HTS filter improves the losses of about 0.2 dB with respect to the copper one.

Compact slot antenna for ultra‐wide band applications

A novel compact ultra-wide band antenna with L-shaped slot is presented. The printed antenna is fed by a microstrip feed line to achieve impedance matching for the SMA connector. The proposed antenna offers 118% bandwidth when printed on a substrate of dielectric constant 4.4 and has an overall dimension of 23.7 × 23.7 × 0.8 mm3. The simulated and measured reflection characteristics of the antenna with the variation of key-parameters along with radiation patterns of the final antenna are presented and discussed. In addition, by decreasing the dimension of radiating patch, band-notched properties in the lower wireless local area network (WLAN) (5.15–5.35 GHz) or higher WLAN (5.725–5.825 GHz) bands are achieved. With the compact size and broadband, this antenna is very suitable for using in a trade-off which has to be taken account for a design of miniaturisation.

Technique of Coaxial Frame in Reflection for the Characterization of Single and Multilayer Materials with Correction of Air Gap

Techniques based on fixture probes in reflection are used in microwave reflectometry as a novel diagnostic tool for detection of skin cancers, for complex permittivity measurements on liquid samples and oil shale, and for complex dielectric permittivity of animals’ organs and tissues measurements in microwave band for the needs of modern veterinary medicine. In this work, we have developed a technique to characterize multilayer materials in a broadband frequency range. A coaxial probe in reflection has been specially developed for microelectronic substrate. Using SMA connector, loss tangent of 10−4and relative permittivity have been measured with an error of 0.145%. The extension of the coaxial probe in reflection technique to multilayer substrates such as Delrin and Teflon permitted to measure bilayer material provided the good knowledge of electrical parameters and dimensions of one layer. In the coaxial transmission line method, a factor that greatly influences the accuracy of the results is the air gaps between the material under test and the coaxial test fixture. In this paper, we have discussed the influence of the air gaps (using samples of 0.5 mm air gaps) and the measures that can be taken to minimize that influence when material is measured. The intrinsic values thus determined have been experimentally verified. We have described the structure of the test fixture, its calibration issues, and the experimental results. Finally, electromagnetism simulations showed that the best results can be obtained.

DUAL-BAND CPW-FED CIRCULARLY POLARIZED SLOT ANTENNA WITH IMPROVED GROUND PLANE STRUCTURE

In this letter, a new design of dual-band circularly polarized (CP) slot antenna is proposed. By embedding a vertical stub, a T-shaped strip and a slit to the ground plane, the CPW-fed slot antenna can radiate right-handed circularly polarized (RHCP) wave in two bands 3.0GHz and 5.0GHz. The designed antenna with a size of 33 £ 27 £ 1mm 3 is fed by a 50-Ohm SMA connector and fabricated on a low-cost FR-4 substrate. Experimental results show that the measured 10-dB return loss impedance bandwidths are 20.4% for the lower band and 23% for the upper band, and the measured 3-dB axial-ratio (AR) bandwidths are 14.1% and 15.8%, with respect to 3GHz and 5GHz, respectively.

Coplanar Waveguide-Fed Broadband Microwave Devices with (or without) a Thin Dielectric Substrate for Use in Flexible Electronic Systems

Two examples of microwave devices, fed by a coplanar waveguide and realized on a thin substrate (or without such a substrate), are employed to investigate the influence of devices’ curvatures and the proximity of different materials on their parameters. To perform the tests, a broadband antenna and a low-pass filter are chosen. A feeding coplanar waveguide is realized on a dielectric material brick attached to an SMA connector and the main device structure is placed in the air or on a thin substrate. The utilization of a thin substrate or its removal from the structure gives rise to the possibility of placing the devices on curved surfaces. The investigated devices are redesigned and manufactured. The antenna has a total size of 46 mm × 44 mm and covers a frequency range of 2.4–35 GHz which gives a 174% fractional bandwidth. The filter has a total size of 50 mm × 80 mm and its bandwidth has a cutoff frequency of 3.4 GHz. The obtained results are verified by measurements and good agreement is achieved.

Space Difference Magnetic Near-Field Probe With Spatial Resolution Improvement

To achieve good spatial resolution, small loop size is required in the traditional loop probe. However, the smaller loop size will lead to lower sensitivity for the probe. In addition, loop size is always limited by the minimum line spacing of the fabrication process. Another problem is that the asymmetric electric field coupling into a probe will not be canceled perfectly even if the structure of this probe is symmetric. To circumvent these problems, a space difference magnetic near-field probe with three kinds of spatial resolutions is proposed in this paper. The probe head including a one-turn loop and a two-turn loop is manufactured in low temperature co-fired ceramics (LTCC). The one-turn loop is clamped with the two-turn loop. Two loops are covered with two shielding ground plates to form a tri-plate structure. The received signals from these two loops are outputted with two SMA connectors through two striplines. The flip-chip junctions with low loss and good shielding capability are used between the probe head and the striplines. The probe characteristics are measured using a 436- μm-wide microstrip line with impedance of 50 Ω. Two output ports have different spatial resolutions because two different loops are located above the microstrip line at different height. The proposed probe will have higher spatial resolution when the received signals are outputted in difference. These results are also verified by measuring a 2000- μm-wide straight and a 500- μm-wide meander microstrip line. The experiment results have good agreement with the simulation results and show the resolution improvement of the difference output of the proposed probe for different lines.

A Compact Novel Tapered U Slot Ultra Wideband Antenna

This paper presents the design and results of a novel, compact and miniaturized tapered U slot UWB printed monopole microstrip antenna for wireless applications. The planar, small and thin UWB antenna fed by a single 50Ω microstrip line with truncated ground plane is excited by a coaxial SMA connector. The correct feed position is determined for impedance matching. The simulation was done using Ansoft High Frequency Structure Simulator (HFSS) software. The simulated results of impedance bandwidth, radiation patterns and group delay are well supported by measurement. Extensive investigations are also carried out on the same antenna design by varying the dimensions to reduce the overall size of the antenna for miniaturization and the UWB performance parameters are studied. The antennas are fabricated and the measured impedance bandwidths defined by VSWR＜2 are 10.34GHz (3.66-14GHz) and 10.60GHz (3.4-14GHz) on FR4 substrate.

Design and Analysis of Tripple Band Koch Fractal Yagi Uda Antenna

The proposed antenna is Koch fractal printed Yagi-Uda antenna fed by SMA connector. The radiation characteristics of the antenna are simulated by CST Microwave Studio and analysed with the help of simulated results. The antenna's currents distribution becomes more uniform after being fractal, which is conducive to increase the antenna’s radiation directivity. The proposed Koch fractal Yagi-Uda antenna resonance at frequency of 7.81 GHz, 8.54 GHz and 9.42 GHz with gain of 9.67 dB, 10.4 dB and 10.61dB respectively. Parameter of antenna such as return loss, input impedance, smith chart, radiation pattern is analyzed for performance evaluation of Koch fractal Yagi-Uda antenna. DOI: http://dx.doi.org/10.11591/ijece.v3i4.2572

Design and development of a small compact ultra wideband antenna

In this paper the design of a novel and compact U slot UWB printed monopole microstrip antenna of size 19.2 × 28.8 mm2 has been presented for wireless applications. The planar, small and thin UWB antenna design consists of a U slot radiator fed by a single 50Ω microstrip line with truncated ground plane is excited by a coaxial SMA connector. The simulations are done using the Ansoft High Frequency Structure Simulator (HFSS) software tool. The simulated results of impedance bandwidth are well supported by measurement. The measured group delay and radiation pattern results are also presented and performance of the antenna is analyzed/discussed.

A Wideband Cavity-Backed Elliptical Printed Dipole Antenna With Enhanced Radiation Patterns

A new wideband unidirectional cavity-backed elliptical printed dipole antenna with enhanced radiation patterns is proposed. The cavity utilized in the proposed antenna is a simple cylindrical cavity, which can generate broadside radiation patterns. An elliptical printed dipole director is placed in front of the elliptical printed dipole antenna for improving the radiation patterns in the upper frequency band. The antenna is fed by an SMA connector through a step-tapered balun accomplishing a transition from a microstrip line to a parallel stripline. The antenna is fabricated and measured. Results show that the antenna achieves an impedance bandwidth of 129.7% for VSWR ≤ 2.0 from 1.55 to 7.27 GHz. Stable unidirectional radiation patterns with an antenna gain of 8.04-13.27 dBi, low back radiation, and low cross polarization are found over the operating frequencies.

RECONFIGURABLE SIW ANTENNA BASED ON RF-MEMS SWITCHES

In this article, a novel compact reconfigurable antenna based on substrate integrated waveguide (SIW) technology is introduced. The geometry of the proposed antennas is symmetric with respect to the horizontal center line. The electrical shape of the antenna is composed of double H-plane SIW based horn antennas and radio frequency micro electro mechanical system (RF-MEMS) actuators. The RF-MEMS actuators are integrated in the planar structure of the antenna for reconfiguring the radiation pattern by adding nulls to the pattern. The proper activation/deactivation of the switches alters the modes distributed in the structure and changes the radiation pattern. When different combinations of switches are on or off, the radiation patterns have 2, 4, 6, 8, . . . nulls with nearly similar operating frequencies. The attained peak gain of the proposed antenna is higher than 5 dB at any point on the far field radiation pattern except at the null positions. The design procedure and closed form formulation are provided for analytical determination of the antenna parameters. Moreover, the designed antenna with an overall dimensions of only 63.6 × 50 mm2 is fabricated and excited through standard SMA connector and compared with the simulated results. The measured results show that the antenna can clearly alters its beams using the switching components. The proposed antenna retains advantages of low cost, low cross-polarized radiation, and easy integration of configuration.