In this paper, a broadband bowtie-based log-periodic array antenna is proposed and investigated for 5G millimeter wave (mmwave) applications. Using a Glass Integrated Passive Device (GIPD) process the proposed antenna is implemented on a high dielectric constant glass substrate. To address the directional radiation issues associated with the traditional straight connection, the proposed antenna uses a crisscross connection effect with carefully spaced three dipole elements. Furthermore, the use of bowtie-based dipole offers a wide bandwidth advantage. The study also examines the effects of changes in key parameters on critical antenna features. The feeding structure uses a combination of coplanar waveguide (CPW) and microstrip line to strip line. For demonstration, a prototype antenna is optimized, fabricated, and measured. The measurement results show that the 10 dB impedance bandwidth of the proposed antenna is from 21.5 to 36.1 GHz, and the gain is higher than 5.63 dBi.
INTRODUCTIOND ue to its natural characteristics, such as wide bandwidth, high data rates, and strong directional characteristics, millimeter-wave (mm-wave) technology has significantly contributed to the advancement of fifth-generation (5G) mobile communication technology [1,2]. The 3GPP Release 15 standard has defined the n257, n258, and n261 5G-NR FR2 bands for 5G mm-wave communication applications [3]. These frequency bands offer advantages such as high-speed data transfer, low-latency communication, and coverage in densely populated urban areas. They are suitable for various applications, including data centers, cloud computing, the Internet of Things (IoT), the Internet of Vehicles, remote healthcare, and industrial automation [4][5][6][7].The dielectric properties have a significant impact on the performance of millimeter-wave antennas. With its stable dielectric constant and low loss, glass serves as an ideal substrate due to its advantages in integration, accuracy, stability, and surface finish [8]. It is well suited for the use in portable and mobile devices and can withstand harsh weather conditions during operation. When being seamlessly integrated into structures such as windows and displays, the glass antennas enhance millimeterwave signal transmission without altering the appearance, thus overcoming the challenges of signal loss and obstruction. In addition, glass is a cost-effective and widely used material that shows promise for achieving efficient and cost-effective mmwave communication in 5G networks.Recently, several 28 GHz antennas utilizing a glass substrate have been demonstrated to enhance reliability and decrease fabrication complexity and cost [9][10][11][12][13][14][15]. In [9], a 28 GHz Yagi-Uda antenna is designed, achieving a measured gain exceeding 3.44 dBi with a relative bandwidth of over 28.2%. In [10],