Indoor Antenna Research Articles

Tracking System for Indoor TV Antenna Based on CVBS Signal Processing

Analog terrestrial TV is still a popular choice for urban societies although the migration to digital system has already begun. Video quality of analog TV was heavily influenced by performance of the antenna. Most users prefer to use indoor antenna due to its simplicity. The disadvantage of this type of antenna is the users may need to change the antenna direction repeatedly when they change to different TV channel. In this research, we designed and developed tracking system that enable indoor TV antenna to adjust its direction automatically to get optimum video clarity. This system is built by several servo motors and telescopic antennas. Composite Video Baseband Signal (CVBS) processing is used to obtain reference information regarding video clarity level conditions on TV screen. The results show that CVBS signal processing has performance in describing video clarity level. System performance has been verified from trial results on some UHF channels. Minimum tracking time is reach 23.4 second and the maximum reach 24.6 second.

Dual-Polarized Indoor Antenna for Digital TV Reception

Dual-Polarized Indoor Antenna for Digital TV Reception

A Review on Monopole and Dipole Antennas for In-Building Coverage Applications

This paper presents a review of several antennas topologies applied for indoor applications. Few requirements are desired for those antennas fo rtheir suitability for indoor applications. Such as antenna size, antenna profile, simple structure, omnidirectional radiations, polarization, and sufficient bandwidth to cover the most wireless communications bands, including GSM, LTE, WLAN ,WiFiand WiMAX. This paper focuses on minimizing the number of antennas needed to cover all these frequencies while offering convenient polarization to mitigate the fading problems and multipath effects losses. To meet these requirements, a monopole antenna with circular polarization is suggested. In addition, various topologies of monopole and dipole antennas are discussed in this paper in terms of their advantages and challenges. Moreover, this review is helpful to understand the current developments in indoor antenna topologies and it proposes a new antenna with a sufficient design for modern indoor applications.

Design of metallic parabolic anechoic chamber for compact range measurement

Anechoic chambers are used for indoor antenna measurements. The common method for anechoic chamber construction is to cover all inside walls by the EM absorbers. A fully metallic parabolic chamber is presented in which the propagation of the EM waves inside the chamber is controlled and they are guided to an absorber. In the proposed method, an appropriate quiet zone with plane wave illumination is obtained, and unlike ordinary anechoic chambers the absorber usage is decreased greatly. The performance of the chamber is evaluated by simulation and the results showed that the proposed method could provide a useful technique for the compact range antenna measurements.

Metallic spherical anechoic chamber for antenna pattern measurement

Anechoic chambers are used for indoor antenna measurements. The common method of constructing an anechoic chamber is to cover all inside walls by the electromagnetic absorbers. In this paper, a fully metallic spherical chamber structure is presented in which the propagation of the electromagnetic waves inside the chamber is controlled and they are guided to an absorber. In the proposed method, an appropriate quiet zone is obtained, and unlike ordinary anechoic chambers, the absorber usage amount is reduced greatly. The performance of the chamber is evaluated by simulation. The results show that the proposed method could provide a useful technique for the indoor antenna measurements.

Bandwidth Enhancement of a Monopolar Patch Antenna With V-Shaped Slot for Car-to-Car and WLAN Communications

A monopolar patch antenna with a V-shaped slot for car-to-car (C2C) and wireless local area network (WLAN) communications is presented in this paper. To widen the impedance bandwidth of the antenna, techniques for adding a shorting pin and a V-shaped slot are applied to an equilateral triangular patch. By properly placing the shorting pins on an equilateral triangular patch, two operating modes, i.e., TM10 and TM20, are obtained. The presence of the V-shaped slot can generate an additional TM11 mode. These three resonances found in the operating frequency bandwidth resulted in a wideband characteristic. The proposed antenna can operate from 4.82 to 6.67 GHz for the reflection coefficient $\le -$ 10 dB with the gain of around 5.0 dBi. In addition, an omnidirectional radiation pattern is yielded by a coaxial center-fed probe excitation. The antenna has a thickness of 0.09 $\boldsymbol{\lambda}_\mathbf{g}$ (at the center frequency of 5.5 GHz), which is easily hidden on the roof of a vehicle for C2C communication. This proposed design can also be used as indoor base-station antennas for WLAN communication.

Modernising, Upgrading and Recommissioning the Indoor Antenna Range at Stellenbosch University

This paper describes the upgrade to the indoor antenna range at Stellenbosch University. The previous measurement process relied upon obsolescent control equipment and undocumented software; it was critical that these be replaced. Now, the antenna range supports three measurement types using a commercial integrated measurement control system that provides support for high gain and low gain antennas over a wide frequency range. These are spherical near-field, planar near-field and conventional far-field measurements, with the potential to implement cylindrical near-field. The antenna range potentially supports operations from 1 GHz up to 26.5 GHz, though the currently available probes do not cover the full band. The main physical upgrade was performed during October 2014, though investigations had already begun in 2011, and some supplementary tasks were still ongoing at the time of writing. Several innovative commissioning tests have been undertaken, some of which are only possible with near-field metrology, and these are described in the paper.

Design of a dual-band indoor antenna with orthogonal bi-directional radiation pattern

Design of a dual-band indoor antenna with orthogonal bi-directional radiation pattern

Using Metallic Ellipsoid Anechoic Chamber to Reduce the Absorber Usage

Indoor antenna measurements in classic anechoic chambers necessitate electromagnetic (EM) absorbers to cover the internal walls. An alternative fully metallic ellipsoid chamber structure is presented that controls the EM wave propagation to generate an appropriate quiet zone by guiding waves into a simple spherical absorber. The simulated performance demonstrates a significant reduction in absorber usage.

Achievable Gains of Directional Antennas in Outdoor-Indoor Propagation Environments

We present an empirically based model for the gain of an indoor antenna array. This corresponds to the re-parametrization of the Greenstein-Erceg model, as applied to 5 m-50 m narrowband outdoor-indoor links. Our model is applicable to a few adjacent tones in an OFDM femtocell system such as LTE. We find that as much as 14 out of 16 dB of antenna-gain are attainable even in rich indoor scattering conditions. At the same time, no larger fade margin is required when using the array vs. the omnidirectional antenna. To provide a reference for the observed results we consider a simple propagation model, which is analyzed theoretically and via simulation. This model is found to match our empirical results very well.

Indoor positioning with GPS and GLONASS-like signals use of new codes and a repealite-based infrastructure in a typical museum building

In order to propose a solution for the indoor positioning question, several tests with the repealite-based (similar to Pseudolites and repeaters) system have been carried out. This system uses a single Global Navigation Satellite System signal transmitted by all the indoor antennas. These signals may interfere with the satellite ones outdoors. Hence, the noise level at the outdoor receiver will be higher and the error range larger. To avoid these effects, new codes called Indoor-Modified Binary Offset Carrier codes that are capable of reducing interference with outdoor signals are generated. To analyse the performance of these codes, we carry out a theoretical expression of cross-correlation functions. Then the deployment of the repealite based system in a typical building is simulated. The goal of this step is to compare the interference performance of the new code with the one already used (Gold codes for GPS band and maximal sequence for Glonass one). A specific interest is given to the spectral interference when adding the new signal’s spectrum in the considered frequency band.

Interference to DTV reception from FM radio signals

Interference to DTV reception from signals in the 88-108 MHz FM broadcast band has been observed since the end of analog TV broadcasting in June, 2009. This interference is generated in the front-end (tuner) of the affected receiver. This paper describes the non-linear mechanisms in the receiver by which FMI to DTV reception takes place. The author has tested 15 models of NTIA approved DTV down-converters measuring the increase in DTV received signal power required as a function of the power of local off-air FM signals in his laboratory. He has also tested "amplified indoor antennas" and found their performance was seriously impaired by FMI. This work was carried out as unsponsored research.

후면 패치를 갖는 광대역 사다리꼴 모노폴 안테나의 설계

본 논문에서는 PCS/WCDMA/WiBro/S-DMB(1.750<TEX>${\sim}$</TEX>2.655 GHz) 공용 모노폴 안테나로서 사용 가능한 광대역 모노폴 안테나를 제안한다. 제안된 안테나는 FR-4 기판에 제작된 사다리꼴 모노폴 안테나의 후면에 패치를 추가하여 대역폭을 개선시킨다 제안된 안테나의 광대역 특성과 복사 패턴을 확인하기 위하여 설계된 안테나를 제작하고 복사 특성을 측정하여 계산된 결과와 비교하였다. 측정 결과는 계산 결과와 비슷하게 나타났으며, 사용대역 내에서 2 dBi 이상의 이득을 가지며, 1.73<TEX>${\sim}$</TEX>3.48 GHz 대역(중심 주파수 기준 67.2 %)에서 1.5:1 이하의 VSWR을 갖는 것으로 나타났다. 본 논문에서 설계된 모노폴 안테나는 PCS/WCDMA/WiBro/S-DMB 공용 실내용 안테나로 사용할 수 있을 것으로 생각된다. In this paper, a wide-band monopole antenna for use in PCS/WDCMA/Wivro/S-DMB(1.750<TEX>${\sim}$</TEX>2.655 GHz) band is presented. The presented antenna is a trapezoidal monopole antenna which has back-side patch and improves the bandwidth. To confirm the wide-band characteristics and radiation pattern of presented antenna, the experimental antenna is fabricated and its radiation characteristics are measured, compared with calculated results. It is shown that the designed antenna has VSWR less than 1.5, gain over 2 dBi in 1.73<TEX>${\sim}$</TEX>3.48 GHz. The measured results show good agreement with calculated results. From the result, we confirm that the designed antenna can be used indoor antenna for PCS/WCDMA/WiBro/S-DMB.

Antennas for the New Airwaves

The paper gives an overview of different indoor and outdoor antennas that can be used for TV applications. An emphasis is given on the antennas that can be used for HDTV and digital TV.

디지털 TV 실내수신 환경 분석

지상파 디지털 방송신호는 기존 아날로그 방식과 달리 상당히 낮은 C/N(Carrier to Noise Ratio)에서도 좋은 화질의 수신이 가능하다. 최근 디지털 튜너 기술의 발전과 함께 수신 가능한 임계 전계강도가 낮아지는 추세에서 실내 안테나를 이용한 실내수신 가능 세대가 늘어나고 있다. KBS에서는 주택환경에 따른 실내에서의 DTV 수신환경을 조사하기 위해 수도권지역에서 DTV 실내 수신환경에 대한 필드테스트를 실시하였다. 측정 대상 가구는 통계청의 자료에 의해 가구 비율을 선별하여 거리별로 총 58개 지점을 선정하였으며, 일반적으로 사용자들이 많이 사용하는 방식의 지향성, 무지향성 안테나와 많이 보급되고 있는 칩셋(chip set)이 내장된 셋톱박스(set top box)를 이용하여, 다양한 수신 조건에서 측정을 수행하였다. 본 논문에서는 측정 결과의 분석을 통해 각 측정 지점에서의 지형적 요인, 가옥의 구조 등에 따른 수신 전계강도의 변화와 공동주택의 층별 차이, 주변 건물의 입지조건 등에 따른 수신환경의 변화 등을 확인하였고, 실내 수신환경에 적합한 전파 조건 및 수신 방법 등을 정리하였다. 조사결과는 지상파 DTV의 실내 수신 확대를 위한 기본 자료로서 활용될 예정이다. DTV has a great advantage as compared to Analog TV in picture quality under low reception field strength. Various high quality tuners have been developed to result in much smaller Noise Figure of the receivers and many trials for receiving DTV signal through indoor antenna. In this paper, results of intensive field tests on the indoor reception of DTV are presented. Tests were carried out around Seoul-Gyeonggi Metropolitan area. Commercial directional and omni-directional antennas and 5th generation receiver were used for reception availability tests. The effects of heights, locations, and types of the house as well as the distance to the transmitter on the reception performances are analyzed. Our test results will be applied to improve the indoor reception environment of DTV.

폴디드 단락 스터브를 갖는 십자형 모노폴 안테나의 복사 특성

본 논문에서는 광대역 십자형 모노폴 안테나를 제시하고 복사 특성을 고찰하였다. 제시된 모노폴 안테나는 십자형 구조의 복사 소자와 폴디드 단락 스터브로 구성되어 있으며, 기존의 십자형 모노폴 안테나보다 우수한 대역 특성을 갖는다. 제시된 안테나의 광대역 특성을 확인하기 위하여 주파수 <TEX>$1.75\sim2.655\;GHz$</TEX>에서 안테나를 설계 제작하고 복사 특성을 측정하였다. 제시된 안테나는 수평면내 무지향성, 수직면내 지향성 특성을 가지며, VSWR은 사용주파수 전대역에서 1.5 이하, 안테나 이득은 <TEX>$2.17\sim4.87\;dBi$</TEX>로 나타났다. 이 결과로부터 제시된 안테나는 PCS, WCDMA, Wibro, 위성 DMB 밴드의 공용 실내 안테나로 사용될 수 있는 광대역 특성을 갖는 안테나로 확인되었다. In this paper, the broadband cross monopole antenna is presented and the radiation characteristics are investigated. The presented broadband cross monopole antenna is composed of the cross monopole element and the folded short stub, which has a excellent band characteristics more than the existing cross monopole antenna. To conform the broadband characteristics of the presented antenna, the experimental antenna is designed, fabricated, and its radiation characteristics are measured in <TEX>$1.75\sim2.655\;GHz$</TEX>. It is shown that the designed antenna has the nondirectional pattern in the horizontal plane, the directional pattern in the vertical plane, VSWR less than 1.5, and gain in <TEX>$2.17\sim4.87\;dBi$</TEX>. From these results, the presented antenna is conformed as a broadband indoor antenna which can be used for PCS, WCDMA, Wibro, and satellite DMB band.

Measurement of indoor antennas using GTEM cell

Characterization of indoor antennas has become a current issue, especially with digital television (DTV). The GTEM (Gigahertz transverse electromagnetic) cell, originally made to test equipment for electromagnetic immunity (EMI), is often available to CE designers. The device is also suited for measurement of relatively small indoor television antennas including those with integrated amplifiers.

An Urban Field Strength Survey at Thirty and One Hundred Megacycles

A description is given of the transmitter and receiver equipment used in making field strength surveys in the Camden-Philadelphia area for a low power transmitter whose antenna is 200 feet above the ground, at frequencies of thirty and one hundred megacycles. Field strength contour maps for the area within approximately ten miles of the transmitter are given. From these maps the average field strength obtained at various distances from the transmitter was determined, and the attenuation of the signal was found to be proportional to the 1.84 power of the distance for thirty megacycles and the 2.5 power of the distance for one hundred megacycles for the region between one and ten miles from the transmitter. Curves showing the variation from the average field strength of the signal along three routes radiating fifteen miles from the transmitter are given, and these variations are compared with the elevation profiles of the respective routes. It is shown that the signal is usually strongest on the brows of hills facing the transmitter. Measurements were made in three representative residences, and from these data, curves showing the power required at the transmitter to furnish one hundred microvolts input to receivers with short indoor antennas located in houses at various distances up to ten miles from the transmitter were computed for the two frequencies.