Log-periodic Dipole Array Research Articles

Design of a Compact Log Periodic Dipole Array Antenna for Broadband and High-Power Beam Synthesis Using Superposition

This paper investigates various array beam shapes for high-power electronic warfare applications using an actual broadband array antenna. For use in a limited mounting space, a compact printed log periodic dipole array (LPDA) operating over a wide bandwidth is designed. The LPDA is then extended to an 8 × 1 array, with active element patterns (AEPs) obtained through simulation and measurement. Beam synthesis is performed by the superposition of several array patterns, which involves adjusting the weight of each AEP. To derive a synthesized array beam shape that is similar to the guided mask, the Taylor window weighting method is applied to each array pattern. Finally, beam synthesis for the flat-top beam, cosecant-squared beam, and iso-flux beam is performed using Taylor window-weighted AEPs, and the results are compared with those of beam shapes using ideal isotropic patterns. The results demonstrate that various beam shapes can be achieved for high-power electronic warfare applications using the AEPs of an actual array antenna.

Mutual coupling effects in 2×2 antenna array for ground penetrating radar on multilayered soil

<span>Caral stands as the Americas’ oldest city, boasting a heritage spanning 5,000 years. Over time, various natural forces have woven a complex geological stratum. To gain a deeper understanding of the Caral civilization, non-intrusive exploration methodologies like ground penetrating radar (GPR) are beginning to be used. This method safeguards the integrity of ancient subterranean remains. A GPR system is in development, tailored to the <br /> [200-500] MHz range, employing a 2×2 antenna array with dual polarization. These features enhance resolution without compromising penetration depth. However, using multiple antennas within complex, multi-layered environments introduce impedance band constraints and exacerbates antenna coupling issues. This study assesses the coupling of two antenna candidates: the Vivaldi with defected ground structures (DGS) and the log periodic dipole array (LPDA). The scattering parameters show that the LPDA antenna performed better considering measured and simulated data. Cross-polarization exhibited a broader bandwidth in the LPDA antenna, evident in both simulated and measured data. Additionally, a comprehensive comparison of GPR simulations for each antenna type within an 11-level multilayer medium, with different electromagnetic properties, further highlights LPDA. This antenna boasts a 209 MHz bandwidth and a coupling better than -23 dB for the cross-polarization configuration, firmly showing its best performance.</span>

A Low-Cost Printed Log-Periodic Dipole Array for DVB-T2 Digital TV Applications

A printed log-periodic dipole array (LPDA) for DVB-T2 Digital TV applications, covering the whole DVB-T2 UHF band from Channel 21 to Channel 69 (470 MHz–860 MHz), is presented. The presented antenna offers a compact size and a lower cost compared to both wire and similar printed LPDAs, with a normalized area of only 0.26 λ2 (where λ is the free-space wavelength at the central frequency) and a similar (or higher) average gain. It is composed of meandered radiating dipoles, and it is implemented on FR4, the cheapest dielectric substrate available on the market. Moreover, the antenna size has been reduced to an A4 sheet dimension (210 mm × 297 mm) to cut down the production cost. The antenna has been designed starting from Carrel’s theory and using a general-purpose 3D CAD, CST Studio Suite. The results show that the proposed antenna can be used for broadband applications (≈74% bandwidth) in the whole operating frequency band of Digital TV, with a satisfactory end-fire radiation pattern, a stable gain, and a radiation efficiency over the required frequency range (average values 6.56 dB and 97%, respectively).

Gain Anomaly Mitigation in Coaxial-Fed Log- Periodic Dipole Array Using Wideband Φ-Shaped Balun

Gain Anomaly Mitigation in Coaxial-Fed Log- Periodic Dipole Array Using Wideband Φ-Shaped Balun

An Optimization Design of Bi-log Hybrid Antenna with Taguchi’s Method for EMI Measurements

This paper presents a comprehensive design approach for a biconical log-periodic dipole array (Bi-log) hybrid antenna optimized specifically for electromagnetic interference (EMI) measurements. The antenna’s elements, scaling function, feed structure, balanced-to-unbalanced (Balun) geometry, and key parameter selection are carefully considered to achieve enhanced broadband testing capabilities. The proposed compact Bi-log hybrid antenna is optimized using Taguchi’s method within the frequency range of 30 MHz to 6 GHz. The optimization focuses on the discontinuity of the antenna factor (AF), incorporating miniaturized elements. The dimensions of the proposed antenna are minimized, with a length of 95 cm, width of 148.5 cm, height of 60 cm, and weight of 2.5 kg. Simulation results and experimental validations demonstrate its efficacy through comparison. Optimization results indicate that the voltage standing wave ratio VSWR < 2 (with 5 dB attenuator) and symmetry < ±0.5 dB also meet the regulatory standards according to ANSI C 63.4. This makes the proposed antenna suitable for use in various types of semi-anechoic chambers.

A Novel Compact High Gain Wide-Band Log Periodic Dipole Array Antenna for Wireless Communication Systems

This paper implies a prototype for a broad-band log periodic dipole antenna (LPDA) with dimensions of 20 × 40 × 0.508 mm3 equipped with directors. The LPDA is based on Roger’s RT5880 with εr = 2.2. The 4-arms with alternative stubs constitute the LPDA, which is evenly spaced on both lines. At the substrate’s back, the 50Ω main feeder line is placed on partial ground. The directors are also incorporated and studied in a regular matrix at a predetermined distance to improve gain, further reduce side lobes, and widen the frequency band. The performance of the antenna covers a wide spectrum of millimeter waves ranging from 26 up to 44 GHz. The realized gain for the antenna is 8.97, 11.96, 13.96, and 14.29 dB at 28 GHz, 35 GHz, 38 GHz, and 43 GHz, respectively. The total gain is 14.29 dB as a peak gain. The antenna was designed and tested for 5G communication applications in autonomous vehicles, and the design cost for the antenna is low in comparison to dielectric lenses. The model exhibits symmetrical radiation patterns for the antenna range. The results of the simulations and the testing of the implemented antenna elements coincide quite well. The proposed design outperforms earlier work in this field.

Design and Analysis of LPDA Fed Parabolic Reflector Antenna

In this research, a parabolic reflector antenna fed by a log-periodic dipole array (LPDA) was designed for the broadband requirement in the space very long baseline interferometry (SVLBI) project. Geometric parameters for LPDA and reflector were calculated and selected based on the major performance indicators, then the simulation and results were obtained in the software ANSYS Electronics 2021. The realized antenna gain exceeded the engineering requirement of 15 dB, and related issues were also studied and analyzed.

Design a Compact Printed Log-Periodic Biconical Dipole Array Antenna for EMC Measurements

This article presents the design, modeling, and fabrication of a printed log-periodic biconical dipole array antenna (PLPBDA) for electromagnetic compatibility (EMC) measurements. The proposed structure used bow tie-shaped dipoles instead of typical dipoles to achieve a size reduction of 50% and bandwidth enhancement of 170% with the help of PCB technology. Furthermore, the balanced feeding method and the modifications in bow tie-shaped dipole dimensions were utilized to obtain broad bandwidth of 5.5 GHz (from 0.5 GHz to 6 GHz). This structure comprises 12 dipole elements with a compact size of 170 × 160 × 1.6 mm, reflecting low fluctuations gain of about (4.6–7) dBi with the help of an extra dipole. Moreover, the achieved frequency and radiation characteristics (simulated and measured) agree with each other and are compatible with the results of classical EMC antennas. The achievements of this structure showed promising results compared to both literature reviews and reference antenna Hyper LOG® 7060 offered for sale.

Design of Log Periodic Dipole Array with FEM and FDTD Based Analysis for GSM, PCS, Industry Standard Medical and Wi-Fi Communication Applications

There is a need of low profile and multiband antennas in various fields of wireless communication lower band applications. Suitable gain with higher data rates for future communication modules in compact range is most challenging for design engineers. In this paper, Log Periodic Dipole Array antenna was designed and proposed for frequency range from 900 MHz to 2.6 GHz, operating frequency for the proposed antenna is 0.9 GHz (GSM), 2.1 GHz (PCS) and 2.4 GHz Industry standard Medical (ISM) and Wi-Fi applications. The modelled antenna constructed on FR4 substrate with height of 1.6mm, and analysed with electromagnetic simulation software like Magus, CST (Computer Simulation Technology) and HFSS (High Frequency structure simulator) tools. The proposed antenna has advantages like wideband, simple design, antenna results indicate the reflection coefficient value below -10dB for whole band from 900 MHz to 2600 MHz. The proposed antenna showing overall gain of 6 dB. Several antenna parameters are evaluated in Finite Element Method (FEM) and Finite Difference Time Domain (FDTD) and provided comparative analysis in this work.

Optimized LPDA Antenna for IoT Applications

In this new era of fast-growing industry revolution, IoT has become integral part of most industries. In this paper, a high directivity printed log periodic dipole array (LPDA) antenna printed on a FR4 substrate is proposed for the application of IoT communication. The simulation result of NSGA-II optimized antenna is then compared and validated with another optimization scheme, MOEA\\D algorithm. The simulation results demonstrate that the proposed antenna has low sidelobe level of -13.9dB with the VSWR < 2 across the dual bandwidth of 0.3027 GHz and 5.6289 GHz from 4.2166 GHz to 4.5193 GHz and 5.8412 GHz to 11.47 GHz respectively. The proposed antenna has achieved a new low side lobe level of -13.9 dB. It is also possesses a wide bandwidth which enhanced from 2.52GHz to the dual bandwidth of 0.3027 GHz and 5.6289 GHz on 4.2166 GHz to 4.5193 GHz and 5.8412 GHz to 11.47 GHz respectively. It has a good realized gain of 8.42dBi with the increment of 1.42dBi after optimization. The multi objective genetic algorithm optimizes the realized gain, directivity, sidelobe level, bandwidth, standing wave ratio of the proposed antenna which is well suited for practical applications in physical layer IoT communication.

A high gain multiband offset MIMO antenna based on a planar log-periodic array for Ku/K-band applications

An offset quad-element, two-port, high-gain, and multiband multiple-input multiple-output (MIMO) planar antenna based on a log-periodic dipole array (LPDA) for Ku/K-band wireless communications is proposed, in this paper. A single element antenna has been designed starting from Carrel’s theory and then optimized with a 50-Ω microstrip feed-line with two orthogonal branches that results mainly in a broadside radiation pattern and improves diversity parameters. For experimental confirmation, the designed structure is printed on an RT-5880 substrate with a thickness of 1.57 mm. The total substrate dimensions of the MIMO antenna are 55 × 45 mm2. According to the measured results, the designed structure is capable of working at 1.3% (12.82–12.98 GHz), 3.1% (13.54–13.96 GHz), 2.3% (14.81–15.15 GHz), 4.5% (17.7–18.52 GHz), and 4.6% (21.1–22.1 GHz) frequency bands. Additionally, the proposed MIMO antenna attains a peak gain of 4.2–10.7 dBi with maximum element isolation of 23.5 dB, without the use of any decoupling structure. Furthermore, the analysis of MIMO performance metrics such as the envelope correlation coefficient (ECC) and mean effective gain (MEG) validates good characteristics, and field correlation performance over the operating band. The proposed design is an appropriate option for multiband MIMO applications for various wireless systems in Ku/K-bands.

A Size-Reduced, Circularly Polarized, Log-Periodic Dipole Array

A single-feed, circularly polarized, log periodic dipole array (CPLPDA) with size-reduced, cross-dipole elements is proposed. Size reduction in elements is achieved with curved T-shaped, top loading. Compared to the full-sized CPLPDA elements, the achieved element-length reduction is 50%. With six elements, the antenna shows a -10-dB impedance bandwidth (IBW) of 87.0%, and a 3-dB axial ratio bandwidth (ARBW) of 50.0% in measurement. The common bandwidth (CBW) between the -10-dB IBW and 3-dB ARBW of the CPLPDA is 50.0%. The peak realized gain in the direction of the shortest element is 6.60 dBi over the CBW.

Data Processing Mechanism and Algorithm Optimization for Radiated Emission Measurement of Electronic and Electrical Equipment

Radiated emission is one of the most important measurement items in the field of electromagnetic compatibility. The measured value of field strength often deviates from the real value to a certain extent. According to the characteristics of typical log-periodic dipole array antenna, the relation between antenna resonance unit and frequency, as well as the position relation between phase center and calibration reference point, the calculation formula of field strength correction factor is derived. The correction factor of field strength in the 30MHz-1GHz is also calculated precisely. The data processing mechanism of radiated emission measurement is clarified. An optimization algorithm for the measurement of radiated emission is obtained eventually. After the test value is optimized by the correction factor, more accurate field strength can be obtained. The optimization interval is within (-0.348, 2.741) dB. As a data processing mechanism of the radiated disturbance, it can not only improve the accuracy of measurement, but also reduce the uncertainty and error.

Redundancy Elimination of the Classic Log-Periodic Dipole Array Antenna by Resonance Point Optimization for a Miniaturized Structure

To axially miniaturize the microstrip log-periodic dipole array (LPDA) antenna, a new design method is proposed. The proposed method redistributes the LPDA’s resonance points, meanwhile reducing the number of dipoles required for a designated bandwidth. The length of each dipole is adjusted according to the proposed design formula to redistribute the resonance points while keeping the bandwidth unaffected. The proposed design method can achieve a considerable size reduction. Two LPDAs with 19 and 15 pairs of dipoles are designed, and they both work at 1–10 GHz. They achieve an axial size reduction rate of 18% and 28%, respectively, compared with the classic LPDA. The versatility of the method is verified in a different band of 2–20 GHz, in which the proposed PRO LPDA with fewer dipoles achieves an axial size reduction rate of 44% compared with the classic LPDA. The proposed design method not only provides mathematical and physical insight into the mechanism of the LPDA but also has directive guidance for antenna engineers.

Landstorfer Printed Log-Periodic Dipole Array Antenna With Enhanced Stable High Gain for 5G Communication

A novel wideband stable high-gain Landstorfer printed log-periodic dipole array (PLPDA) antenna loaded with zero-index metamaterials (ZIMs) is proposed for wireless communication system. Based on the Landstorfer-shaped method, the dipoles and ground of the PLPDA antenna are Landstorfer-shaped and strung together by feeding lines to form a novel Landstorfer PLPDA antenna, which obtains a gain enhancement compared with the PLPDA antenna. To further enhance both the antenna gain and gain flatness, a series of novel ZIM are added to the shorter end of the Landstorfer PLPDA antenna. As an example, four-element Landstorfer PLPDA antennas with/without ZIM are designed, implemented, and measured in Ka-band for 5G application. Compared with the original PLPDA antenna, the proposed Landstorfer PLPDA antenna exhibits a maximum gain enhancement of 2.2 dB within the operating band of 26.5–40 GHz. Loaded with ZIM, the antenna gain can be further improved by 0.5–1.9 dB with a measured gain flatness of 10.5 ± 0.5 dBi over the band of 25.7–40 GHz while the size of antenna keeping unchanged. The proposed antenna presents a stable high-gain performance in terms of the parameter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta G$ </tex-math></inline-formula> /BW ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta G$ </tex-math></inline-formula> is the gain variation, BW is the bandwidth) less than 0.07 within the whole Ka-band.

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

A micro-scaled printed log periodic dipole array (LPDA) antenna is proposed for terahertz (THz) applications. The proposed low profile graphene conductor based LPDA antenna is designed with integrated protudent dipoles to realize super wide bandwidth and high gain characteristics. The suggested THz antenna is designed on a 10 µm thick Rogers RT / Duroid 5880 ™ substrate material of dimension 450 µm × 500 µm. The proposed antenna exhibits 2:1 VSWR operating super wide bandwidth (SWB) of 30050 GHz (0.09–30.14 THz) with a peak gain of 16.02 dBi. The designed antenna shows fractional bandwidth of 199.46% along with a huge bandwidth ratio of 334.88:1. The radiation efficiency balancing from 85% to 98.2% is maintained throughout the whole operating –10 dB SWB (0.09–30.14 THz). Design formulation of the proposed structure, structural parametric analysis, surface current distribution and characteristics parameters are discussed in detail in this paper. The proposed antenna covers the entire frequency band of the terahertz region to support a number of sub-terahertz and terahertz communication applications such as high speed short distance communication, video rate imaging, biomedical imaging, surveillance, mine detection, sensing, and security scanning.

Design and Optimization of Compact Printed Log-Periodic Dipole Array Antennas with Extended Low-Frequency Response

This paper initially presents an overview of different miniaturization techniques used for size reduction of printed log-periodic dipole array (PLPDA) antennas, and then continues by presenting a design of a conventional PLPDA design that operates from 0.7–8 GHz and achieves a realized gain of around 5.5 dBi in most of its bandwidth. This antenna design is then used as a baseline model to implement a novel technique to extend the low-frequency response. This is completed by replacing the longest straight dipole with a triangular-shaped dipole and by optimizing the four longest dipoles of the antenna using the Trust Region Framework algorithm in CST. The improved antenna with extended low-frequency response operates from 0.4 GHz to 8 GHz with a slightly reduced gain at the lower frequencies.

A miniaturized three‐dimensional log periodic Koch‐dipole array antenna using T‐shaped top loading

A log periodic dipole array antenna (LPDA) is miniaturized by using top loading. The Koch dipole further helps to shrink the antenna size. Different from the traditional LPDA that features a planar structure, the proposed log periodic Koch-dipole array (LPKDA) adopts two identical pairs of top-loaded Koch-dipoles that deploy orthogonally along the feed line. This results in a tree-like three-dimensional antenna geometry, which introduces one extra dimension of freedom for antenna designers. The influence of the top-loading on antenna's impedance bandwidth is studied under the Wheeler and Chu's limit. The characteristic of the Koch-dipole is analyzed. Taking the advantage of 3D printing technology to fabricate complex models, the proposed LPKDA is printed by selective laser melting using aluminum alloy. The simulated −10-dB bandwidth is 117.4% (0.91-3.54 GHz) The LPKDA has the average gain of 5.3 dBi over the 1 to 3.5 GHz impedance bandwidth in measurement. Radiation patterns agree well in simulation and measurement. Compared with conventional LPDA of the same impedance bandwidth, the proposed LPKDA features 42%-dimensional reduction. This letter proves the feasibility of antenna optimization by using both innovative design method and advanced fabrication process.

Miniaturised band notched printed LPDA design with meander fractal dipole for UWB communication

ABSTRACT In this paper, a miniaturised band-notched Printed Log Periodic Dipole Array (PLPDA) is designed with fractal dipole for UWB Communication. The miniaturisation is achieved using Meander fractal geometry applied to each dipole element of the PLPDA. The sub-sectional tapered concept is integrated to achieve notches in the WLAN band (5.15 GHz-5.825 GHz) and the WiMAX band (3.4 GHz-3.6 GHz). A broad bandwidth of 7.78 GHz is achieved here by using this fractal geometry-based band-notch concept. The structure of UWB-PLPDA is fabricated on a RO3003 substrate material. Initially, a surface area reduction of 79% in the case of PLPDA with sub-sectional tapered dipole and later, a surface area reduction of 82% with improved performances in case of PLPDA with meander line fractal, are achieved compared to the simple PLPDA design. The simulated design models are physically fabricated, and the measured results found in good agreement with the simulated results. The proposed miniaturised PLPDA is a suitable candidate for high-speed-short-range wireless communications.

DIFFERENTIAL-FED LOG-PERIODIC DIPOLE ARRAY WITH HIGH ISOLATION FOR WIDEBAND FULL-DUPLEX COMMUNICATIONS

DIFFERENTIAL-FED LOG-PERIODIC DIPOLE ARRAY WITH HIGH ISOLATION FOR WIDEBAND FULL-DUPLEX COMMUNICATIONS