Mobile Communication Frequency Band Research Articles

High isolation 4‐port MIMO sloted antenna for Sub‐6 GHz wireless applications

AbstractAiming at the application of Sub‐6 GHz band, this paper presents a high isolation four‐port MIMO slot antenna with CPW feeding mode. About this antenna, two parallel binary antennas are oppositely arranged with connected ground, and isolation branches are adopted to improve isolation. Each element antenna is realized through elliptical shape patch and trident structure feed line. The measured results show that its working frequency band is 1.82–6.5 GHz band, with ports isolation less than −20 dB. In addition, its other performance parameters are good, such as gain of 7.03 dB and ECC parameter below 0.004, and CCL is less than 0.3 bps/Hz. The antenna has high isolation and it can not only work in the mobile communication frequency bands such as n41, n77, n78, and n79, but also work in the frequency band of the IoT, such as WiFi5, V2X, and DSRC.

Train-mounted Broadband Monopole Antenna for 5G Communication

As a convenient and efficient public transport system, high speed railway (HSR) was rapidly deployed in China. Since the fifth generation (5G) mobile communication system is commercially applied, it is necessary for mobile terminals antennas to cover multiple operating bands to be compatible with various communication systems. Here a HSR-mounted broadband and high-gain monopole antenna is proposed. By using the meander technology and introducing the tapered structure, the proposed antenna operates over a bandwidth of 694-960 MHz and 1350-5975 MHz (VSWR<1.8), which covers both 2G-5G mobile communication and WiFi frequency bands. The dimensions of the proposed antenna are 400 mm × 330 mm × 78 mm. The measured average gain is 6.11 dBi over the entire bandwidth.

A novel high-performance diplexer for mobile communication base stations

In this paper, a novel design of a diplexer for mobile communication base station is proposed, theoretically investigated and successfully tested. The proposed design of the diplexer is implemented on the base of interdigital filters. Successfully fabricated and tested diplexer operates within frequency bands 2.3–2.4/2.49–2.69 GHz and shows high performances: reflection loss within pass bands is less −20 dB, insertion loss is −0.15 dB, isolation is −30 dB and intermodulation is −124 dBm. Computer-aided design of the diplexer is carried out on the basis of combined technique, which includes filter synthesis using coupling matrices, eigenvalue problem solution for single resonator, interresonator coupling calculation and final full wave simulation and optimization of diplexer. The suggested design is a promising candidate for the implementation of diplexers with narrow, moderate and wide bandwidths for standard mobile communication frequency bands.

Design and Simulation of vehicle antenna in different frequency band

In order to meet the needs of a variety of automotive communication services, vehicle antennas working in multiple frequency bands are emerging. It promotes the development of antenna in the direction of multifrequency and miniaturization. Based on the above research background, this paper designs a vehicle antenna for the requirements of mobile communication frequency band. The antenna consists of a half-t monopole and a half cone monopole, which are vertically placed on a metal floor. T-shaped branches mainly work at low frequency, while cone-shaped branches mainly work at high frequency. The tapered branch is used to improve the impedance matching, increase the bandwidth of the antenna, and the antenna miniaturization is realized by using half reduction technology. The antenna is processed and measured, and the working frequency bands are 720MHz-960MHz and 1.6GHz-4GHz, covering amps, GSM, LTE and 5G.

Inset Fed Triple Band U- Slot Antenna For Gsm900/Gsm1900/Wlan Applications

To cover Global System for Mobile Communication(GSM) and WLAN frequency bands, three distinctive Inset fed antennas like rectangular microstrip, dualband dual slot and antennas are designed. Inset fed micostrip antenna is used for GSM1900 with an impedance bandwidth from 1.90GHz to 1.96GHz. Inset fed dual band dual slot antenna is used for GSM1900 and WLAN with impedance bandwidth is considered first band from 1.90GHz to 1.95GHz and second band from 2.38GHz to 2.42GHz. The proposed Inset fed triple band antenna is used for GSM900, GSM1900 and WLAN with appropriate position of slot, is to operate in frequency ranges of first band is from 920MHz to 940MHz, second band is from 1.91GHz to 1.94GHz and third band is from 2.39GHz to 2.43GHz. A correlation among various feed widths, feed lengths and slot widths are exhibited in this paper.

Pre-Clinical Testing of Microwave Radiometer and a Pilot Study on the Screening Inflammation of Knee Joints.

This article presents the pre-clinical evaluation of our custom-built, single-band microwave radiometer centered at 1.3 GHz for deep tissue thermometry, and a pilot study on volunteers for passive detection of inflammation in knee joints. The electromagnetic (EM) compatibility of the battery-operated radiometer for clinical use was assessed as per International Special Committee on Radio Interference (CISPR) 22 standard. The ability to detect inflammation in knee joints was assessed using a substrate integrated waveguide antenna connected to the radiometer. EM compatibility tests carried out in the laboratory indicated device immunity to intentional radiated interference up to -20 dBm injected power in the global system for mobile communication frequency band, and pre-compliance to CISPR 22 standard. Radiometer temperature measurements recorded at the lateral and medial aspects of both knees of 41 volunteers indicated mean temperature greater than 33°C for the diseased sites compared with the mean temperature of 28°C measured for the healthy sites. One-way analysis of variance statistics indicated significantly (P < 0.005) higher radiometer temperature at the diseased sites unlike the healthy sites. Thus, the EM pre-compliance of the device and the potential to measure deep tissue inflammation were demonstrated. Bioelectromagnetics. 2019;40:402-411. © 2019 Bioelectromagnetics Society.

A Coplanar Microstrip Antenna as a Dosimetric E-field Probe for GSM Frequencies

The present article discusses the measurement results of a coplanar microstrip antenna used as an electric field (E-field) probe. The E-field measurement is used to calculate the Specific Absorption Rate (SAR) of the tissue equivalent liquids exposed to uniform E-field strength in a transverse electromagnetic cell. The antenna used as an E-field probe resonates at the two important frequencies of the Global System for Mobile communication frequency band i.e. 915 MHz and 2.10 GHz. The simulation of the antenna has been carried out on EM simulation software, HFSS. The experimental and simulation results are found to be in good agreement for return loss. The E-field measurement results along with expanded uncertainties are compared with standard dipole results. Finally, the SAR values are computed for the in-house tissue equivalent liquid.

Design and characterization of microstrip based E-field sensor for GSM and UMTS frequency bands.

An Electric (E-) field sensor based on coplanar waveguide-fed microstrip antenna to measure E-field strength for dual-band operation at 914 MHz and 2.1 GHz is proposed, designed, and characterized. The parametric optimization of the design has been performed to obtain resonance at global system for mobile communication and universal mobile telecommunication system frequency band. Low return loss (-17 dB and -19 dB), appropriate gain (0.50 dB and 1.55 dB), and isotropic behaviour (directivity ∼ 1 dB), respectively, at 914 MHz and 2.1 GHz, are obtained for probing application. Antenna factor (AF) is used as an important parameter to characterize the performance of the E-field sensor. The AF measurement is explained in detail and results are reported. Finally, using the designed E-field sensor, the E-field strength measurements are carried out in a transverse electromagnetic cell. The key sources of uncertainties in the measurement are identified, evaluated, and incorporated into the final results. The measurement results are compared with theoretical values, which are found in good agreement. For comparative validation, the results are evaluated with reference to an already calibrated commercially available isotropic probe.

Design of a dual-polarized wideband antenna for 2G/3G/4G mobile communication base station application

A wideband dual-polarized antenna for 2G/3G/4G mobile communication base station systems is presented in this article. The proposed antenna is composed of two pairs (four) of metal sheets as the main radiation elements. Downward stubs at the end corners of the metal sheets are used to reduce the size of the antenna and for the convenience of tuning. Cylinder with slots is placed at the center of the antenna as balun. Cable is used for the feeding and part of the outer conductor is removed for tuning. An antenna prototype was fabricated. The measured results show that a bandwidth of 53% (1.70–2.95 GHz) for VSWRs < 1.5 is obtained for both polarization ports, which can cover the 2G/3G/4G mobile communication frequency band (1.71–2.69 GHz). The isolation between two ports is larger than 28 dB and the radiation patterns of the antenna are stable over the entire operating frequency band (1.71–2.69 GHz). © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1329–1332, 2016

English

Antennas are one of the most important parts of a communication chain. They are used for both communication and calibration purposes. Antenna measurement techniques involving near-field probes have been a recently developing area. New developments in probe technologies have enabled near-field probes with much larger bandwidth. The objective of this Master's Thesis is to design, simulate and fabricate a dual polarized wideband inverted quad ridged shape horn antenna which can be used as measurement probe for near field measurements. Typical probes like Open Ended Waveguides, dipole antenna probes etc are bulky in mobile communication frequency bands. In addition they are narrow band probes. The inverted quad-ridged horn antenna probe not only provides measurement in the much wider range but also provides dual-polarization measurement thus enabling antenna developers to measure UWB, UHF, VHF antennas more precisely and at lower cost. The antenna is designed to meet the characteristics such as high gain, light weight, linearly polarized with suppressed side lobes for near-field measurement applications. The proposed antenna is simulated with commercially available packages such as Ansoft HFSS. The antenna gives a moderate gain over operating range while delivering a wide bandwidth.

Effects of Mobile Phone Radiation onto Human Head with Variation of Holding Cheek and Tilt Positions

This paper analyzed the effects of electromagnetic (EM) radiation mobile phone on human head with different holdingpositions. The EM radiation is measured in terms of specific absorption rate (SAR). The human head exposed toglobal system for mobile communication (GSM) frequency bands. The radiation absorption analyzed throughsimulations by applying finite-difference time domain (FDTD) method using computer simulation technology (CST)microwave studio. The specific absorption rate (SAR) was measured for two common holding positions of mobilephone: Cheek and Tilt. In this tilt position, the mobile phone tilted for 15° and 30° from a person’s head. SARsexhibited in much lower values as the mobile phone held in cheek position than that of tilt position. Helical antennawith substrate of Rogers RO3006 (loss free) found to be best tested substrate by resulted in lower SAR due to itslower conductivity properties than that of RO4003.

A Wideband Printed Directional Antenna Array with Impedance Regulating Load

We proposed a broadband directional antenna array working at mobile communication frequency band, which achieves a relative bandwidth of 50.7%. This binary antenna array is fed by two branches of the balanced microstrip. To enhance the antenna bandwidth, we introduced a section of loading metal strip. The antenna prototype has aS11lower than −10 dB within the 1.5 GHz to 2.52 GHz frequency band, particularly from 2.01 GHz to 2.50 GHz, theS11is lower than −15 dB. The gain varies with relatively small variation within the working band, which is 5.4 dBi to 8.7 dBi.

보안등의 통합 모니터링을 위한 이동통신용 안테나 설계

본 논문에서는 보안등의 통합 모니터링과 제어를 위한 3G 이동통신용 RF모듈에 적용 가능한 반파장 폴디드 슬롯 안테나를 제안하였다. 제안된 안테나는 입력임피던스가 <TEX>$50{\Omega}$</TEX>에 가까운 총 길이가 <TEX>${\lambda}g$</TEX>인 전형적인 폴디드 슬롯 안테나의 장점을 유지하면서 절반의 크기를 가지고 PCB의 가장자리에 위치할 수 있도록 변형된 폴디드 슬롯 구조이다. 제안된 안테나는 국내 3G 이동통신 대역용으로, <TEX>$40.5{\times}62mm^2$</TEX>의 기판 중 상단 <TEX>$40.5{\times}10mm^2$</TEX>의 공간을 이용하여 설계 및 제작하였다. 제작된 안테나를 측정한 결과, 390 MHz의 대역폭, 2 dBi의 이득을 얻을 수 있었다. In this paper, a half-wavelength folded-slot antenna, which can be applied to RF module for 3G mobile communications by which security lights are monitored and controlled, is proposed. The proposed antenna can be regarded as modified folded-slot structure which has the size reduced to a half of conventional <TEX>${\lambda}g$</TEX> folded-slot antenna and can be placed at the ground plane edge. In spite of that, the proposed antenna still maintain the advantage of conventional folded-slot antenna that input impedance is close to <TEX>$50{\Omega}$</TEX>. The antenna is designed and fabricated within the upper space of <TEX>$40.5{\times}10mm^2$</TEX> on <TEX>$40.5{\times}62mm^2$</TEX> substrate for 3G mobile communication frequency band. The measured impedance bandwidth and antenna gain are 390 MHz and 2 dBi respectively.

781MHz 대역에서 안테나 상관도를 고려한 개선된 MIMO 채널 특성 분석 방법

In this paper, the measurement data is analyzed and channel characteristics are derived through MIMO Channel measurements at 781MHz considering antenna correlation. 781MHz frequency band currently operates the DTV system, however, it will be allocated new mobile communication frequency band. The channel characteristics at 781MHz seem to be similar existing mobile communication system at 900MHz but quite a different part of the existing research has demonstrated. In addition, the signal procedure of the channel characteristics, considering the correlation of the antenna, for a more accurate prediction research is needed. To avoid interference with Korean DTV broadcasting, we measured channel characteristics in urban areas of Jeju island by channel sounder and antenna. Channel characteristics with antenna correlation were derived based on the measured data in the urban area.

781MHz 대역에서 MIMO 전파 채널 측정 및 분석

Abstract In this paper, the measurement data is analyzed and channel parameters are derived through MIMO Channel measurements at 781MHz considering outdoor multi-path environment. 781MHz frequency band currently operates the DTV system. However, it will be allocated new mobile communication frequency band. The channel characteristics at 781MHz seem to be similar existing mobile communication system at 900MHz but a study on channel characteristics of signal transfer process is necessary because there is incomplete study in mobile networks at 781MHz. To avoid interference with Korean DTV broadcasting, we measured channel characteristics in city/suburban areas of Jeju island by channel sounder and 4×4 antenna of the ETRI(Korea Electronics and Telecommunications Research Institute). Path Loss, Delay Spread, Angular Spread and K-factor were derived based on measured data. Key Words : MIMO, Path Loss, Delay Spread, Angular Spread, K-factor * 준회원, 충북대학교 전파공학과 ** 준회원, 한국전자통신연구원 전파기술연구부 ***

직렬 급전된 두 개의 다이폴 배열 안테나의 대역폭 향상

본 논문에서는 이동 통신용 기지국 안테나로 사용할 수 있는 직렬 급전된 두 개의 다이폴 배열(STDA) 안테나의 대역폭 향상에 관해 연구하였다. 제안된 STDA 안테나는 두 개의 서로 다른 길이의 스트립 다이폴 안테나가 코플래너스트립라인 급전선으로 바로 연결되어 있다. 두 다이폴 사이의 간격과 두 번째 다이폴의 길이를 조정함으로써 대역폭을 증가시킬 수 있다. 또한, 급전부를 최소화하기 위해 단락이 종단된 마이크로스트립라인과 슬롯라인으로 구성된 내장 밸런을 사용하였으며, 급전위치를 조정하여 광대역 임피던스 정합을 얻을 수 있었다. 제안된 구조로 현재 운용되는 이동 통신 주파수를 모두 포함하는 1.75-2.7 GHz 대역에서 이득이 5dBi 이상인 안테나를 설계하고 FR4 기판(비유전율 4.4, 두께 0.8 mm)상에 제작하여 특성을 실험하였다. 제작된 안테나는 VSWR<2 기준으로 임피던스 대역폭이 49%(1.7-2.8 GHz)이고 5.5 dBi 이상의 이득을 가지며, 12 dB 이상의 전후방비를 가진다. In this paper, bandwidth improvement of a series-fed two dipole array(STDA) antenna applicable for mobile communication base station antennas is studied. The proposed STDA antenna consists of two strip dipole antennas with different lengths which are connected directly trough a coplanar stripline(CPS). By adjusting the spacing between the two dipoles and the length of the second dipole, the bandwidth of the STDA can be enhanced. In addition, an integrated balun composed of a short-circuited microstrip line and a slot line is utilized to minimize the area required for a feeding part, and a broadband impedance matching is obtained by adjusting the feeding point. Based on the proposed antenna structure, an STDA antenna covering the frequency band ranging from 1.75 GHz to 2.7 GHz, which includes almost all the existing mobile communication frequency bands, with more than 5 dBi gain is designed and fabricated on an FR4 substrate with dielectric constant of 4.4 and thickness of 1.6mm, and experimentally tested. The fabricated antenna shows impedance bandwidth of 49%(1.7-2.8 GHz) for VSWR<2, a gain higher than 5.5 dBi, and a front-back ratio better than 12 dB.

Analysis of the performance of vegetation barriers to reduce electromagnetic pollution

Public fear of exposure to electromagnetic fields has led to many countries introducing legislation on the topic. Some have even introduced ‘sensitive areas’ where field levels should be significantly reduced. This study presents an efficient and ecological method to reduce the exposure to electromagnetic fields for the mobile global system for mobile communication (GSM) and universal mobile telecommunications system (UMTS) frequency bands. We propose the use of tree (or bush) barriers as a shielding method around places that may need to be protected. A major measurement campaign has provided a significant amount of data to characterise the performance of such soft walls. The campaign involves seven vegetation species and five different barrier configurations. Furthermore, a parametrical characterisation of the attenuation levels achieved with this method is presented and validated. This aids in choosing the configuration barriers and the vegetation species that provide the desired attenuation levels in exclusion zones.