Low Voltage Standing Wave Ratio Research Articles

Analyzing Troubleshooting of BTS Transmit Power and 4G LTE Coverage Area via VSWR Value Measurement

The Voltage Standing Wave Ratio (VSWR) serves as a comparative measure between transmitter and receiver voltages, impacting site transmit power. VSWR values at a Radio Base Station (RBS) are evident in feeder cable losses, jumpers, combiners, and radio antenna losses. This study aims to assess the impact of poor VSWR values on BTS transmit power and perform troubleshooting analysis on 4G signal quality and Coverage Area. The study commenced with a literature review and VSWR measurements in the Gurun Laweh Aia Pacah region. The process involved identifying VSWR issues at the BTS site, conducting a Drive Test using pocket Tems, and troubleshooting the VSWR problem. Drive Test findings encompassed areas with weak signals, BTS site data, and problematic spots. The analysis utilized applications like Tems Discovery and MapInfo Pro. Results along the Gurun Laweh Aia Pacah road showed signal strength affected by a high VSWR value of 1.6. RSRP data rated 50% in the good category, SINR at 31% in the good category, and throughput at 5% in the good category. Elevated VSWR values diminish signal range, subsequently impacting traffic metrics. Immediate VSWR troubleshooting becomes imperative; low VSWR promotes higher transmit power efficiency, while normal VSWR ensures optimal transmit power efficiency.

Engineering Designs of Dual-Polarized Antennas With Reduced Profile and Mutual Coupling for 5G Microcell Application

In this letter, a miniaturized, low profile and low mutual coupling antenna array with stable radiation pattern for fifth-generation microcell is presented. The antenna element contains three parts, folded dipole radiator, vertical feeding baluns, and reflector. Four striplines with end connections and stepped slots etched on the main radiator are adopted to enhance the impedance bandwidth and miniaturized the antenna's aperture in the low-profile configuration. While folded stripline structure is applied to reduce the mutual coupling in dual-polarized antenna. The height of proposed antenna is only 0.1 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the free-space wavelength referring to the center operation frequency) and the antenna's aperture is only 0.4 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.4 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> . Measured results show that the antenna array has good performances, exhibiting low voltage standing-wave ratio (VSWR < 1.5), high isolation (> 30 dB), and wide bandwidth (3.2–3.9 GHz, 20%). Stable radiation patterns are measured across the operating bandwidth.

Effect of Symmetric Shaped Slot on Patch Antenna Design and Performance for 10 GHz 5G Applications

A microstrip patch antenna is considered the most suitable radiating and receiving element for millimeter-wave application due to its low cost, simple construction, low weight, and ease with which it is integrated into the circuits. In this paper, we have reported the effects of different symmetric shaped slots on millimeter-wave patch antenna design and its performance at 10 GHz frequency in the X band (8-12 GHZ). The rectangular, circular, and elliptical slots area is kept constant at 11.2 mm2. The radius of circular and spherical slots is the same. High-frequency simulation software (HFSS) simulation results in parameters like S11 (reflection coefficient), Y-parameter (driving point admittance), Radiation Pattern, 3D Polar plot and illustrate that the results are in good agreement with the desired value. A rectangular slot is found to achieve the target resonance frequency with a low voltage standing wave ratio (VSWR) towards a ‘good match.’ Circular, spherical, and elliptical-shaped slots have high VSWR values, indicating a larger degree of mismatch. Surprisingly, results are obtained for the spherical-shaped slot, implying that the antenna will work at the target resonance frequency and has a Dual-Resonance. The proposed antenna design is suitable for 5G device applications in the X band.

A Broad Bandwidth Metamaterial Pillbox Window for W-Band Traveling-Wave Tubes

A low voltage standing wave ratio (VSWR) broad bandwidth pillbox window with metamaterial is proposed for W-band traveling-wave tubes (TWTs) in this paper. The metamaterial structure is designed on a dielectric surface, which decreases the VSWR and broadens the bandwidth of the pillbox window. The cold-test results of the window with metamaterial are presented, which showed that the metamaterial pillbox window (MPW) achieves a bandwidth of 31.5 GHz with VSWR below 1.2, and a bandwidth of 18 GHz with VSWR below 1.1. The ghost mode and the power capacity of the window were also investigated. The results showed that the proposed metamaterial pillbox window is suitable for medium power TWTs. A Ka-band MPW was fabricated and the test results agreed well with the simulation results.

Fabrication of Horn Antenna for Microwave Application

This paper contains a novel design of a horn antenna control system for microwave applications. Using “Fermat’s principle” the horn antenna is designed and fabricated. For microwave applications, high gain and low voltage standing wave ratio(VSWR) is needed, so for that purpose horn antenna is fabricated. In a previous paper, they designed the Yagi Uda antenna which is used for multiple driven elements by the method called maximum power transmission efficiency. For multiple driven elements, the horn antenna cannot be fabricated. If suppose yagi uda is fabricated using the principle called Fermat's, the system can't achieve more gain and low voltage standing wave ratio. Yagi uda antenna can achieve only a high voltage standing wave ratio. To reduce the problems in the existing paper, our paper designs a horn antenna to achieve high gain and low voltage standing wave ratio( VSWR) which is used for microwave applications to transmit microwaves from a waveguide out into space or collect microwaves into a waveguide for the reception.

Demonstration of W-Band 30-W Continuous-Wave Folded Waveguide Traveling Wave Tube with Lowered Operation Voltage and Improved Gain Flatness

We have demonstrated and developed a W-band 30 W continuous-wave folded waveguide traveling wave tube (CW FWTWT) with 13.5-kV operation voltage and 4.8 dB gain flatness. In this paper, we quantitatively study the relationship between operating voltage and the key geometric dimensions of a folded waveguide, which is the key to the design of the low-voltage TWT. In addition, problems of improving beam transmission and suppressing oscillations are also studied, and the related design methodologies of the long-range electron gun, periodic permanent magnet (PPM) focusing system, low-voltage standing wave ratio (VSWR) coupling system, and horseshoe attenuator are discussed. On the basis of the above analysis, we have designed and fabricated two types of W-band CW TWTs. The test results show that beam transmissions are over 98.5% at DC and better than 96.5% at the highest peak RF power. Measured saturated output powers are greater than 33.6 W with saturated gain more than 42.2 dB within frequency range of 91–99 GHz, and an improved gain flatness of 4.8 dB is achieved.

A Full-Band Digital Television Transmitting Antenna Array With Dual-Layer Bowtie Dipole Unit

A full-band digital television (DTV) transmitting antenna array with dual-layer bowtie dipole unit is proposed in this paper. The dual-layer bowtie dipole is utilized as the antenna unit to broaden the frequency bandwidth, and its key parameters are discussed. Besides, a wideband impedance matching network with stepped complex impedance transformers is designed to achieve the full-band low voltage standing wave ratio (VSWR). For verification, a prototype is designed, fabricated, and measured. The experimental results agree well with the simulations. The measurement shows a relative bandwidth of 62.4% (455 MHz - 868 MHz) under the criterion of VSWR <; 1.15. Particularly, the VSWR is less than 1.13 within the range of 470 MHz - 862 MHz, (i.e. the full band of the DTV transmitting system). And the proposed antenna maintains a stable gain larger than 11.6 dBi over the operating frequency band with the half-power beam width of $70^{\circ } \pm ~3^{\circ }$ in the horizontal plane, which meets the requirements of the full-band signal transmission in the DTV broadcasting system.

Design of an Archimedes spiral antenna for PD tests under repetitive impulsive voltages with fast rise times

Partial discharge inception voltage measurements under repetitive impulsive voltages play an essential role in evaluating the reliability of inverter-fed low voltage rotating machines. Using impulsive voltages, partial discharge (PD) signals and the disturbance induced by power electronics switches have often similar energy distribution in the frequency domain. Thus, PD test technologies used with sinusoidal voltages are no longer effective. Under repetitive impulsive voltages, ultra-high frequency detection is recommended to couple high-frequency spectral components from the PD and remove the low-frequency disturbance coming from power electronics. However, to obtain high signal to noise (S/N) ratio, the parameters of the antenna used for PD detection should be designed considering the PD and the disturbance energy distributions in the frequency domain. In this paper, we discuss the design and show the properties of an antenna with Archimedes plane spiral structure intended for PD detection under repetitive impulse voltages. The simulation shows that the antenna has low voltage standing wave ratio (<2) and improved directivity in the frequency range from 0.5 to 2 GHz. Moreover, PD tests performed using repetitive square waves with different rise times demonstrate that the designed antenna can receive PD signals efficiently with high S/N.

Canceling the Cross-Polarization of the Difference Modes in a Circular Aperture Multimode Monopulse Feed

A highly efficient circular aperture multimode monopulse feed is proposed. TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> and TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> modes in the circular waveguide are added in a circular waveguide TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> mode dual-channel monopulse feed. Optimal mode ratios (both amplitude and phase) are realized conveniently to cancel the crosspolarization of the difference modes on the feed's aperture, which changes a low-efficient funnel-shaped difference beam to an azimuth or elevation difference beam with the efficiency of which highly improved. The fundamental HE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> mode of the corrugated waveguide is adopted as the sum mode. The simulation and measured results show that this feed is of low voltage standing-wave ratio, high sum-difference isolation, high transmitter-receiver isolation, high efficiency, and broadband.

A Miniaturized Base Station Antenna With Novel Phase Shifter for 3G/LTE Applications

This paper presents a new type of miniaturized base station antenna array, which consists of a metal reflector, six upper-band dipoles, and a couple of ladder sidewalls, operating over 1.71–2.69 GHz (DCS/PCS/UMTS/LTE). Meanwhile, this paper also proposes a novel miniaturized phase shifter with one input and five outputs to enable the antenna array to achieve electrical downtilt (0°–10°) in the operating frequency band. Three different sidewalls are applied in the proposed antenna array to compare their performance. Simulated results demonstrate that the antenna array with ladder sidewalls can achieve an excellent performance, and this proposed phase shifter also has good electrical properties to help the proposed antenna array realize downtilt. The proposed antenna array and phase shifter are fabricated and measured, and the measured results show that the antenna array has good radiation characteristics, including low-voltage standing wave ratio ( 31 dB), low third-order passive intermodulation (3 30 dB), and high cross-polarization discrimination at ±60° azimuth (>11.5 dB) in all frequency bands and electrical downtilt angles. The proposed antenna array exhibits an acceptable gain of 15 ± 1.1 dBi across the operational frequency band.

A Novel Dual-Broadband Dual-Polarized Electrical Downtilt Base Station Antenna for 2G/3G Applications

A novel dual-broadband dual-polarized base station antenna array with compact structure and low profile is proposed in this paper for the existing mobile communication system operating over 0.79–0.96 GHz (European Digital Dividend/CDMA/GSM) and 1.71–2.17 GHz (DCS/PCS/UMTS). The antenna array is mainly composed of five lower-band elements, ten upper-band elements, some U-shaped metal baffles, and a metal reflector with specific shape. In order to reduce the overall size of the antenna array, lower-band element is designed as octagon aperture shape that upper-band elements can be embedded in it. Two kinds of radiation elements (five for each kind of element) are applied in the antenna array as upper-band elements to achieve better radiation performance. The proposed antenna array achieves electrical downtilt (0°–14° and 0°–10° at lower frequency band and upper frequency band, respectively) by adjusting input amplitude and phase of each array element. Measured results demonstrate that the antenna array has good broadside radiation characteristics, including low voltage standing wave ratio (VSWR 28 dB), low backlobe level (>25 dB), high cross-polarization discrimination (>20 dB), and stable radiation pattern with horizontal half-power beamwidth (HPBW) 65° ± 5° at both frequency bands and all electrical downtilt angles. The peak gains of 15.1 and 17.3 dBi are obtained at lower and upper bands respectively. Owing to these advantages, the antenna array is suitable for existing 2G/3G applications in modern mobile communication systems.

Design of a compact wide band microstrip antenna with very low VSWR for WiMAX applications

A single-layer coaxial-fed compact rectangular microstrip antenna with very low voltage standing wave ratio (VSWR) is presented in this paper. The simulated VSWR of the proposed antenna 1.00374 is obtained near the center frequency of the operating band (3.5 GHz). Simulation and measurement results indicate that the bandwidth (simulated: 3.36–3.715 GHz, and measured: 3.295–3.645 GHz) of the antenna exceeds 10% below VSWR 2, when the size reduction of the antenna is about 81.6%. The realized peak gain is obtained about 2.15 dBi at 3.5 GHz. For the verification of the computational results, two designs were fabricated and measured. Good agreements between simulated and measured results were found.

Ultra wideband antenna design using discrete Green's functions in conjunction with binary particle swarm optimisation

The binary particle swarm optimisation (BPSO) in conjunction with the time-domain discrete Green's function (DGF) method is proposed for designing of printed ultra wideband (UWB) antennas. In the DGF method, on one hand, a three-dimensional problem is reduced to a two-dimensional one, and on the other hand, the broadband frequency characteristics of the antenna are achieved with a single simulation run. Furthermore, the spatial discrete representation of the current on the antenna, in the DGF method, facilitates implementation of its combination with the BPSO algorithm. Two different UWB antennas are designed using the proposed approach. First, an antenna is designed to minimise voltage standing wave ratio (VSWR). The experimental result shows that the antenna has a VSWR about <1.5 over the UWB range. Second, an antenna is designed to have not only low VSWR, but also stable radiation pattern over the UWB range. The experimental results show a good impedance matching and stable omnidirectional pattern over the UWB range.

High performance LPF Structure with sharp roll‐off and low VSWR

A symmetrical compact microstrip lowpass filter (LPF) with ultra-wide rejection band and low voltage standing wave ratio (VSWR) using a novel structure of stepped impedance and butterfly-shaped resonators is presented and fabricated. The LPF has a 3 dB cut-off frequency at 1.513 GHz. The series structure of the butterfly-shaped resonators result in a high roll-off rate of 187.8 dB/GHz. By generating multiple transmission zeros, a wide stopband (with 35 dB rejection degree) is achieved. To reach a small circuit, the bended transmission line is properly utilised. Moreover, 171% relative stopband bandwidth and dimensions of 0.087λ g × 0.157λ g (λ g is the guided wavelength at 1.513 GHz) are other specifications of this LPF. In addition, an acceptable match is obtained between the simulated and measured responses. In the end, the LPF achieves a high figure-of-merit of 82288.

Integration of microwave termination based on TaN thin films on ferrite substrates

Integration of microwave discrete devices such as isolators and circulators is highly desired for radar and communication platforms and in particular as components used in transmit and receive (T/R) modules. In those applications, Tantalum nitride (TaN) films are widely used as a surface mounted termination to improve the reliability and performance. In the current work, TaN thin films were directly deposited on polycrystalline ferrite substrate (Ni 0.3 Zn 0.7 Fe 2 O 4 ) to be integrated with isolators or circulators. The deposition conditions were first optimized to obtain suitable sheet resistance and near zero temperature coefficients of resistance (TCR). Next a 50 Ω microwave termination was designed and fabricated using standard photolithography techniques. Broadband measurements show that the terminator has a low voltage standing wave ratio (VSWR) of less than 1.20 in the frequency range of DC-20 GHz. The measured resistance was between 48 and 54 Ω.

TRANSMISSION LINE THEORY AND THERMAL ANALYSIS OF COAXIAL COUPLER FOR TWTS

This paper presents the transmission line analysis, thermal and structural analysis of a multi-section coaxial coupler (MSCC) used in traveling-wave tubes (TWTs) to handle high average power over a wide frequency range. Power transmission through coupler from the device demands very good matching between load and source impedances such that low voltage standing wave ratio (VSWR) is achieved. Modeling of the MSCC for wideband TWTs in commercially software packages takes very long iteration time even in high-end computers. An analytical approach has been developed to model MSCC which takes less iteration time even in ordinary computer. Analytical results have been compared to those obtained from CST microwave studio. Finally, thermal and structural analysis has been carried out to study the thermal aspects for handling high average RF power.

Mutual Coupling Reduction for Two Closely-Space Meander Line Antennas Using Metamaterial Substrate

Two closely spaced printed meander line antennas (MLAs) are developed by using metamaterial loading techniques with reduced mutual coupling. The antenna array built on the metamaterial substrate showed significant size reduction and less mutual coupling compared to similar arrays on conventional substrates. Demonstrated to have left-handed magnetic characteristics, the methodology uses elliptical split-ring resonators (E-SRRs) placed horizontally between the patch and the ground plane with a row of the same type between antenna elements. Measured return loss of the printed antenna with this technique is less than -10 dB from 5.1-5.9 GHz which covers the IEEE 802.11a (5.15-5.35 GHz and 5.47-5.725 GHz) American standard and HIPPER LAN/2 (5.15-5.35 GHz and 5.725-5.825 GHz) European standard. Also this antenna has an omnidirectional radiation pattern, high gain, and very good pattern stability over the operating band. It is shown to have great impact on the antenna performance enhancement in terms of high efficiency, low voltage standing wave ratio, good bandwidth and less mutual coupling between two antennas with a very close separation of about 0.073λ0. Experimental data show a reasonably good agreement between the simulation and measured results.

Design and Implementation of a Quadrifilar Helix Antenna Operating at 0.94GHz

A quadrifilar helix antenna (QHA) operating at 0.94GHz is designed and realized in this paper. The designed QHA consists of four helical conductors which are excited in phase quadrature by employing a Wilkinson divider which shows good performance in return loss and transmission characteristic. According to the designed parameters of the helices and Wilkinson divider, a QHA is fabricated and measured. The measured results demonstrate that the designed QHA has a resonant frequency of 0.94GHz and relative good performances including low voltage standing wave ratio (VSWR), broad beam width and approximate circular polarization are achieved. The designed QHA has simple structure and is suitable for practical application.

UWB TEM horn antenna for the asphalt pavement investigation

A simple Ultra-WideBand (UWB) exponentially-tapered Transverse ElectroMagnetic (TEM) horn antenna is presented for the asphalt detection based on Ground Penetrating Radar (GPR). In order to reduce the reflections from the antenna aperture, some absorbing material is loaded on the outer surface of the conductor. Comparing with the traditional TEM horn antenna, the proposed antenna has a small size and a large impedance bandwidth. Simulated and measured results show that the proposed TEM horn antenna has a low Voltage Standing Wave Ratio (VSWR) below 2 over the whole band from 0.35 GHz to 12 GHz, good radiation characteristics, and small late-time ringing, which can perfectly meet the requirements of the GPR application.

Design of miniaturized broadband and high gain metamaterial patch antenna

AbstractA miniaturized broad bandwidth and high‐gain patch antenna was designed and fabricated using the metamaterial concept via the pattern‐etched upper patch and bottom ground plane in this article. Due to the left‐handed transmission characteristics, the wave propagation along the patch induces the strongest radiation in horizontal direction instead of the vertical direction of the conventional patch antenna. It is shown to have great impact on the antenna performance enhancement in terms of the resonant center frequency obviously reduced about 36.4%, the bandwidth significantly broadened from about 2.9% to about 39.9%, and also in terms of low voltage standing wave ratio. Experimental data show a reasonably good agreement between the simulation and measured results. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2893–2896, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26383