# Progress on Single-Feed Quality Wideband Linear Wire Array  
Lidong Chi  
LinkingE Technologies (Hengqin) Co., Ltd., Zhuhai S19031, China; [EMAIL_ADDRESS] (L.C. ); [EMAIL_ADDRESS] (L.X.) Lingxiao Xie  
LinkingE Technologies (Hengqin) Co., Ltd., Zhuhai S19031, China; [EMAIL_ADDRESS] (L.C. ); [EMAIL_ADDRESS] (L.X.) Zibin Weng  
School of Information and Communication Engineering, Dalian Maritime University, Dalian 116026, China  
[PERSON]  
Correspondence: [EMAIL_ADDRESS] 1223331  
its effectiveness and contributing to its widespread adoption in various military and commercial applications. This early use demonstrated the antenna's high gain and directional capabilities, which were crucial for effective radar detection and reliable communication. As a wire array antenna, the primary limitation of the Yagi-Uda antenna is its relatively narrow impedance bandwidth, typically around 10%. With advances in communication and radar technology, there is an increasing demand for antennas with much broader operational bandwidths. To address this limitation, antenna manufacturers often need to produce a series of Yagi-Uda antennas, each designed to cover a specific portion of the wide spectrum of frequencies required for modern applications [2]. In most cases, a single antenna is preferred to meet the bandwidth requirements of the system. A log-periodic antenna is a type of broadband, directional antenna that can operate over a wide range of frequencies. It consists of multiple elements of varying lengths, arranged in a specific pattern that repeats periodically on a logarithmic scale. This design allows the antenna to maintain consistent performance across its entire frequency range [3; 4; 5]. Log-periodic antennas are commonly used in applications such as television broadcasting, radio communications, and electromagnetic interference testing, where wideband capability and reliable performance are essential. The typical antenna gains for a log-periodic antenna range from about 6 to 8 dBi. Numerous studies have been conducted to refine the design of the Yagi-Uda antenna, resulting in optimized and quasi-Yagi-Uda antennas. Researchers have put extensive effort into increasing the operational bandwidth of the Yagi-Uda antenna, which typically operates within a bandwidth of 10%. Research on broadband Yagi-Uda antennas began with the quasi-Yagi antenna in 1999, wherein [6] introduced a wideband planar antenna on a high-dielectric substrate, compatible with microstrip circuits, achieving 3 dBi to 5 dBi gain over a 48% bandwidth. Innovations in feeding techniques, such as microstrip-to-waveguide transitions, have expanded the relative impedance bandwidth of quasi-Yagi antennas to over 90% [6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17]. Although these antennas, typically designed for millimeter-wave bands above 3 GHz, have gains 3 dB to 5 dB lower than those of classic Yagi-Uda antennas, their broadband improvements have revitalized the Yagi-Uda design. In this paper, the latest developments of the single-feed Quality Wideband Linear (QWL) array antenna are presented. The QWL antenna stands out due to its broadband, high-gain electromagnetic characteristics and structurally robust design. This antenna incorporates a wideband driven element, directors, and reflectors, drawing on principles similar to those applied to the Yagi-Uda antenna. A key feature of this design is the WHEMS-driven element, which provides bidirectional radiation and enables a wide operational bandwidth. The directors, arranged on the same plane, and a reflector designed for impedance matching further enhance the antenna's gain and bandwidth. What distinguishes this antenna from existing designs is its ability to achieve superior performance while maintaining a compact form factor, simple feeding mechanism, low wind resistance, lightweight construction, cost-effectiveness, and structural durability. These engineering advantages make it ideal for a wide range of applications, including wireless communications, satellite systems, and radar technologies.