Log Periodic Technique Research Articles

Capacitive Coupled Frequency Independent Dielectric Resonator Antenna Array for X-Band Applications

A capacitive coupled Dielectric Resonator Antenna (DRA) array based on log periodic technique is investigated experimentally for X-band applications. The Frequency Independent DRA array consists of seven rectangular Dielectric Resonators (DRs). The DRA array has been excited by a series fed microstrip line. Since the resonators are directly coupled to the feed line, it results in more compact and lower loss DRA array. The proposed DRA array has been designed and realized. The measured results are in good agreement with the simulations. The designed array is operating over the frequency range 6.2–12.2 GHz for 2:1 VSWR with the fractional bandwidth 65.2%. The array provides a peak gain of 9.09 dBi with the broadside radiation pattern over the widespread operating band. The proposed design is useful for X-band applications.

Peripheral Slits Microstrip Antenna Using Log Periodic Technique for Digital Television Broadcasting

This paper proposed a new design of log periodic microstrip antenna using peripheral slits for Digital Video Broadcasting applications in DKI Jakarta. Applying peripheral slits can be reduced the dimension of antenna up to 62.6% with its dimension 400 mm x 150 mm using 4 patches in different frequencies. The patches are one another connected using log periodic technique. The measurement results showed that the antenna was operating at frequency ranges of 450 MHz to800 MHz with impedance bandwidth of 350 MHz,VSWR ≤ 2 and return loss ≤ -10dB. The proposed antenna could receive 11 DVB stations with high definition quality pictureand only channel number 24, such as RCTI, Global TV and MNC TV can not reveive signals as expected.

Design of log periodic dielectric resonator array for NATO-K band applications

This paper presents the performance of a Log Periodic Dielectric Resonator Array (LPDRA) for NATO–K band (18–40 GHz) applications. In this paper, a new wide bandwidth antenna with flat conformal characteristics is formed by application of log periodic technique to the series fed electromagnetically coupled rectangular overlaid dielectric resonator array. This LPDRA has been simulated using a CST microwave studio suite 2010. The simulated results show the wider impedance bandwidth, covering the frequency range of 18–40 GHz with a Voltage Standing Wave Ratio (VSWR) less than 2 and radiation efficiency greater than 95%. Its maximum gain is 9.9 dBi at centre frequency 28 GHz. Parametric studies of the antenna with CST microwave studio based design data and simulated results are presented here. The scaling factor of 1.05 has been chosen for this design.

Wideband Log Periodic-Microstrip Antenna with Elliptic Patches

A broadband microstrip antenna based on log periodic technique was conceived and demonstrated practically. The antenna exhibits a wideband characteristic comparing with other microstrip antennas. Over the operation frequency range, i.e. 2.5-6 GHz, a 50 Ω

Microstrip Bandwidth Enhancement Using Log Periodic Technique with Inset Feed

Ketas kerja ini menerangkan berbagai teknik untuk memperbaiki lebar jalur antena mikrojalur. Salah satu teknik yang dibincangkan secara khusus adalah teknik log periodik. Reka bentuk, penyelakuan dan fabrikasi antena log periodik dengan cara suapan inset telah dibincangkan. Antena telah direka bentuk dengan tatasusunan sebelas unsur. Prestasi antena tersebut dikaji dari segi lebar jalur, gandaan relatif kepada antenna dwikutub, pemencilan kutub silang dan lebar alur. Kata kunci: Antena mikrojalur, antena log periodik, antena jalur lebar, lebar jalur, gandaan This paper describes the various techniques to improve the bandwidth of a microstrip antenna. One of the techniques that has been discussed in detail is the log periodic technique. The design, simulation, and fabrication of log periodic antenna (LPA) with inset feed method has been discussed. The antenna has been designed with eleven element array. The performance of the antenna has been investigated in terms of bandwidth, gain relative to a dipole antenna, cross–polar isolation, and beamwidth. Key words: Microstrip antenna, log periodic antenna, wideband antenna, bandwidth, gain

Fractal Koch dipole antenna for UHF band application

AbstractThe fractal Koch curve is one of the popular fractals shape. This article discussed the analysis of the fractal Koch dipole antenna (FKDA) using log periodic technique. The effect of flare angle of the antenna has been described to reduce the antenna size. The antenna is operated at ultrahigh frequency (UHF) band frequency between 460 MHz and 4 GHz. The analysis is based on the number of elements, degree of flare angle, current distribution, and radiation pattern of the antennas. The antenna has been designed and simulated using computer simulation technology (CST) and fabricated using FR4 board. The performance of the antennas has been measured, analyzed, and discussed in this article. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2612–2614, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24702

Design of a log-periodic aperture-fed microstrip antenna array

The narrow bandwidth of a microstrip antenna is one of the important features that restricts its wide usage, although it possesses many advantages such as low profile, light weight, etc. Various techniques have been used to enhance the bandwidth of this kind of antenna. This paper presents a planar microstrip array designed by the log-periodic technique for wideband operation in the frequency range of 1.7–5.5 GHz. The elements of the array are orthogonal patches, aperture coupled fed by a microstrip line. The far-field pattern of the array, for a number of frequencies in the above range, has been computed by a simulation procedure.

Multioctave bandwidth log-periodic microstrip antenna array

The application of the log-periodic technique to the series-fed electromagnetically coupled overlaidpatch array allows antennas with flat conformal characteristics and wide bandwidths to be obtained. A k-β analysis of this and other microstrip array types indicate that the microstrip patch is not an optimum element for log-periodic arrays and that direct connection will result in arrays having a limited bandwidth. The addition of series capacitance to the patch equivalent circuit, implemented by electromagnetic coupling, allows an optimum to be approached. Log-periodic overlaid patch array design and measured results for an array with a 4:1 bandwidth are presented. These, together with a transmission-line analysis, indicate the array-design trade offs available and that the ultimate bandwidth is limited primarily by changes in the input return loss and radiation pattern due to the use of uniform thickness substrates.