Performance Improvement of Printed Log Periodic Dipole Array Antennas

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 communication, several parasitic dipole elements served as director cell are added to the shorter end of the printed Log-periodic dipole array (PLPDA) antenna for the gain enhancement. This novel antenna is based on the combination of the PLPDA antenna and the quasi-Yagi antenna techniques, so called printed Log-Yagi dipole array antenna (PLYDA). The number and the distribution of the director cell are discussed and optimized. A prototype PLYDA antenna fed by half mode substrate integrated waveguide (HMSIW) is manufactured, as well as a HMSIW PLPDA antenna for comparison. The return loss and far-field radiation patterns were measured and presented in this work. The proposed PLYDA antenna exhibits gain enhancement of 0.2-2 dB in comparison with the equal size PLPDA antenna over the operating frequency range 21-40 GHz. The simulated and measured results are in good agreement, and the gain enhancement using the director cell is verified.

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.

Three different V‐band high gain printed log periodic dipole array (PLPDA) antenna prototypes are proposed. The antenna prototypes are fabricated and tested. A good agreement between the experimental and simulated results is obtained. Results show that those antenna prototypes can operate from 42 to 82 GHz with a fractional impedance bandwidth of 64.5% covering the whole V‐band (50–75 GHz). At 60 GHz, the three antenna prototypes have peak gain of 12.64, 23.31 and 26.79 dBi with a gain variation of 3.5 dBi across the whole V‐band with stable radiation patterns over the operating band. The proposed PLPDA antenna prototypes achieve good side‐lobe suppression, excellent front‐to‐back ratio in both E‐ and H‐planes and low cross‐polarisation levels over the entire frequency range.

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.

Design of V-band high-gain printed log periodic dipole array (PLPDA) antenna loaded with a low-cost spherical dielectric lens is introduced. The proposed antenna consists of microstrip-line-fed log-periodic dipole antenna designed to operate in the V-band with a peak gain of 12.64 dBi at 60 GHz. To enhance the antenna gain, a dielectric lens is installed. The antenna prototype is fabricated and then tested experimentally using Agilent E8364B PNA Network Analyzer. Experimental results agree well with the simulated ones. The simulated results show that the proposed antenna can work from 42 GHz up to 82 GHz with a fractional impedance bandwidth of 64.5% covering the whole V-band (50–75 GHz). At 60 GHz, the proposed antenna has peak gain of 26.79 dBi with a gain variation of 3.5 dBi across the whole V-band with stable radiation patterns over the operating band. The proposed PLPDA antenna achieves good side-lobe suppression, excellent front-to-back ratio in bothE- andH-planes, and low cross-polarization levels over the entire frequency range. These unique features will make this antenna suitable for different interesting applications such as millimeter-wave radar and imaging applications.

In this paper, an elliptic metallic patch is presented to enhance the gain of a simplified feeding printed log-periodic dipole array (PLPDA) antenna. The geometry of the elliptic patch is analyzed and optimized for the gain enhancement. The geometric features of microstrip provide a wideband balun, which is applied to feed the high gain PLPDA antenna. The prototype of the proposed high gain simplified feeding PLPDA antenna at Ka band is simulated, implemented and measured. The gain enhancement using the elliptic metallic patch is verified.

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.

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.

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.

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.

A new resonance point optimization (RPO) is applied to reduce the log-periodic dipole array (LPDA) antenna's axial size. The resonance points are redistributed under the premise of the unchanged impedance bandwidth. And the required radiating elements number is reduced. In comparison with the classic LPDA, axial size reduction rates of 18% and 28% are achieved by two proposed RPO LPDAs with a working frequency band of 1-10 GHz. They consist of 19 and 15 elements respectively. An obvious size reduction rate of 44% in the axial direction is obtained through the RPO method at 2–20 GHz. The RPO design technique provides a reference to miniaturize the LPDA axially.

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 signiflcant space reduction of a Planar Log-Periodic Dipole Array (LPDA) is achieved in this work. This reduction was performed by utilizing the flrst order iteration meander shape dipole in the design of a planar LPDA. The minimization procedure is illustrated in this work by presenting two designs for a Euclidean LPDA with linear dipoles and a meander LPDA operating over the entire S frequency band. Both designs are compared through the main common characteristics of an antenna: return loss response, radiation pattern and the maximum gain. The agreement between the results of both designs was very good and the properties of the meander LPDA were identical to those of the Euclidean LPDA.

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.