Analysis of short-wave antenna array characteristics by moment method

A hybrid method using Method of Moment (MoM) and Transmission Matrix (TM) is first time applied in the analysis of log-periodic dipole array antennas (LPDA) in this paper. It utilizes the advantages of both MoM and TM. And this method doesn't need to construct an extended matrix which usually has to be used in other methods. Further more, it has very clear physical meaning. In order to solve the Pocklington's integral equation, an iteration technique is adopted. The effectiveness is demonstrated by calculation the radiation pattern, input impedance, current and voltage distribution of LPDA. The results using this method agree very well with the results of other references.

Currently, the needs of communication system with a wide bandwidth is large enough. One antenna that can be used to realize communication with a wide bandwidth is log periodic antenna. To observe the effect of element length, the distance between elements, and the width of dipole elements used in log periodic antenna then do research to design and realize the antenna log periodic dipole array (LPDA) and log periodic dipole array fractal Koch (LPDAFK) at frequency of 287-324 MHz. The results of the implementation of LPDA and LPDAFK antenna give different results with simulations. On the measurement of LPDA and LPDAFK antennas, antenna operating frequency shifted to a higher frequency. LPDA antenna is working on frequency 295-310 MHz and 360-385 MHz, while the working frequency of the antenna fabrication LPDAFK are 292-304 MHz, 346-354 MHz and 404-414 MHz.

Design and analysis of a super wideband (0.09[formula omitted]30.14 THz) graphene based log periodic dipole array antenna for terahertz applications

In this paper, the design and simulation of a compact printed log-periodic dipole array (PLPDA) antenna operating between 3.4 – 9.5 GHz for VSWR less than 2 is presented. Performance improvement of the antenna is achieved through the use of dipole trimming and parasitic elements. Dipole trimming has resulted in an improved impedance bandwidth while parasitic elements has led to a better gain performance in comparison to the conventional PLPDA. The proposed 12-element low profile PLPDA antenna exhibits high gain of 7.2 – 10.1 dB within the wide operational bandwidth, and a stable directional radiation pattern. The two easy-to-implement performance improvement techniques used in this research has optimized the PLPDA to outperform the conventional PLPDA both in terms of effective bandwidth and gain.

In order to develop medical antenna at sub-terahertz (THz) band, we propose two kinds of novel designs of log-periodic dipole array (LPDA) antenna for enhanced bandwidth and high gain. Instead of typical rectangular dipole form, one is designed with Taeguk dipole for enhanced bandwidth and the other employs circular dipole shape for high gain, The proposed antennas operate at sub-THz band. Taeguk LPDA antenna works over 60 – 100 GHz frequency range. Circular LPDA antenna achieves maximum gain of nearly 10 dBi at 85 GHz.

16 elements of ultra-wideband millimetre-wave printed log-periodic dipole array antenna (LPDAA) which fed by the 4-by-4 Wilkinson power distribution network is designed and fabricated for far distance chipless RFID system application. The LPDAAs are design on single side of the Taconic TLX-8 (□ r = 2.55) with 0.5 mm thickness and the feeding network is design on the same material but with 0.13 mm thickness. The antenna is designed to operate in 20–30 GHz. The total array dimension including its power distribution network is 80 × 78 × 60 mm. Radiation pattern is obtained throughout the measured bandwidth. The measured gain of the array is average at 25 dBi over the frequency range of 20–30 GHz and the cross-polarization ratio is less than −20 dB. The printable structure, low return loss, wide bandwidth and high gain of the proposed array suggest it as a suitable antenna for many applications in mm-wave range including chipless RFID systems.

A novel design of multiple input–multiple output (MIMO) antenna based on the log-periodic dipole array (LPDA) for the mobile handsets is presented. The antenna operates in a wide frequency range of 1.86–3.84 GHz compatible with GSM, LTE, WLAN, and WiMAX. The MIMO design consists of two symmetrical and orthogonal radiating elements and a neutralization line (NL). The radiating element comprises a LPDA having a series of printed dipoles connected together with a microstrip line. Triangular and rectangular cuts on ground plane are carried out in accordance with the LPDAs so as to increase the impedance bandwidth and isolation. The antenna elements are linked with the NL to further enhance the isolation between the radiating elements. The performance of the MIMO antenna is analyzed in terms of S-parameters, radiation pattern, gain, total efficiency, envelope correlation coefficient, mean effective gain, multiplexing efficiency; and then it is verified through the measurements. The results demonstrate that the proposed MIMO antenna has good characteristics of wideband, gain, radiation pattern, isolation, and diversity.

In this paper, the design, simulation and evaluation of a wide band printed log-periodic dipole antenna array, which could be used to detect the presence of radiolytic components of the ubiquitous water molecule, is presented. The antenna was fabricated on an FR-4 substrate. The design was simulated and the characteristics such as the scattering parameter, VSWR, input impedance, etc. studied over a wide frequency band. The radiation pattern in the azimuth and elevation plane was studied at two different frequencies in the L-band of the microwave spectrum. The antenna has a directive pattern, and shows a linearly polarized response. The antenna could be used to monitor the presence of ionising nuclear radiation that can make the neutral water molecules undergo a breakdown sequence into hydrogen peroxide, hydrogen radicals and assorted oxygen compounds, such as ozone, which when converted back into oxygen releases great amounts of energy. The antenna design shows two resonance peaks that are in the frequencies corresponding to the dissociated components, viz. 1.68 GHz and 1.42 GHz.

A new class of microstrip travelling wave antenna of large bandwidth is described. The log-periodic array is composed of flat short-circuited half dipoles acting at quarter-wave resonance and fed in series by means of a high characteristic impedance microstrip line. A model has been constructed and tested. A large squinted main beam is obtained between 0.75 and 4.5 GHz. The constant experimental radioelectric properties are in good agreement with the theoretical predictions.

Precise estimates were previously obtained for the error in the optimum gain of an antenna array arising from errors in the measured noise covariance matrix. It was observed that the error estimates are a function of the character and spatial distribution of the noise field. The purpose of the current work is to analyze this dependence of the previous results upon the quantitative and qualitative aspects of the noise field.

This communication presents a comprehensive numerical analysis of single microstrip antenna and antennas array in spherically layered media, using the method of moments (MoM). The curvilinear Rao–Wilton–Glisson (CRWG) triangular basis functions are employed to simulate the equivalent current on the antenna surface. First, the dyadic Green’s functions using Debye potential are deduced. Then, their efficient computation procedures are carried out to improve calculation efficiency. Finally, the characteristic basis function method is employed to save memory and calculation time by reducing dimension of the impedance matrix. The results of this study are in good agreement with those of the FEKO software, and they show that the method proposed in this communication is more efficient than FEKO in the analysis process.

Antenna array gain is a relative measure of performance defined differently in various literature. Most definitions of gain are not power consistent, and thus cannot be used directly in link budget analysis. In this short paper, we present a power correction factor for common definitions of power gain of antenna arrays that allows them to be used in standard link budget calculations.

There is a growing interest in mm-wave antennas and devices for high data transmission to support the future 5G communication. In this work, we have designed a low profile, high gain, broadband four elements printed log periodic dipole array (PLPDA) working over the range of (24-39) Ghz. In the first part of the design, a PLPDA is designed, which achieved around 10.5 dB gain, 49.6% impedance bandwidth. Later some horn corrugation is cascaded to the PLPDA which enhanced the overall gain up to 13 dB, while 52% impedance bandwidth is obtained. All results are validated using two different numerical packages.

A 10-element, size-reduced, circularly polarized log periodic dipole array antenna (CPLPDA) is presented by decreasing the length of the antenna elements in half using arc-shaped, top-loading structures. The simulated −10-dB impedance bandwidth is 106.5%, and the 3-dB axial ratio bandwidth is 110.4% Both bandwidths are matched well. The maximum realized gain in the direction of the shortest dipole is 7.1 dBic. Compared to a λ/2-element CPLPDA, the miniaturized CPLPDA has 75% volume reduction.

A novel printed log-periodic dipole array (PLPDA) antenna with bow–tie parasitic cell for the gain enhancement is presented for 5G mobile and wireless communication. The antenna is fed by the substrate integrated waveguide. The gain of the antenna is enhanced using parasitic cell—several bow–tie directors and bow–tie parasitic patches. The adding of bow–tie directors are based on the principle of the quasi-Yagi and the bow–tie antenna. Moreover, the parasitic patches are used to enhance the antenna gain by expanding the transverse radiation aperture of the antenna according to the principle of the antenna array. The proposed antenna has been designed, fabricated, and tested. It can be observed that the PLPDA antenna gain with the parasitic cell is increased about 1-dBi compared with the antenna with the single-sided rectangle directors. And the S11 of the proposed antenna is less than −12 dB, the cross-polarization level is better than −15 dB, and the gain of the presented antenna is 7.3–12.5 dBi over the whole operating frequency range of 40–50 GHz.