Abstract
Researchers are increasingly showing interest in the application of a Butler matrix for fifth-generation (5G) base station antennas. However, the design of the Butler matrix is challenging at millimeter wave because of the very small wavelength. The literature has reported issues of high insertion losses and incorrect output phases at the output ports of the Butler matrix, which affects the radiation characteristics. To overcome these issues, the circuit elements of the Butler matrix such as the crossover, the quadrature hybrid and the phase shifter must be designed using highly accurate dimensions. This paper presents a low-loss and compact single-layer 8 × 8 Butler matrix operating at 28 GHz. The optimum design of each circuit element is also demonstrated in detail. The designed Butler matrix was fabricated to validate the simulated results. The measured results showed return losses of less than −10 dB at 28 GHz. The proposed Butler matrix achieved a low insertion loss and a low phase error of ± 2 dB and ± 10°, respectively. In sum, this work obtained a good agreement between the simulated and measured results.
Highlights
Research on the fifth-generation (5G) mobile communication systems has rapidly accelerated to meet the standardization of the International Telecommunications Union Radiocommunication by 2020 and its requirement for higher data rates and data traffic [1,2,3,4]
The design of a single-layer 8 × 8 Butler matrix operating at 28 GHz was proposed for a 5G base station antenna
The Butler matrix is compact with a dimension of 88 × 110 × 0.254 mm3
Summary
Research on the fifth-generation (5G) mobile communication systems has rapidly accelerated to meet the standardization of the International Telecommunications Union Radiocommunication by 2020 and its requirement for higher data rates and data traffic [1,2,3,4]. The features of 5G mobile communication systems include the utilization of millimeter waves, the deployment of small cells with a radius size of 200 m and the use of a multibeam base station antenna for multiple-input multiple-output schemes [2,3,4,5,6,7]. The Butler matrix has received much attention due to its simple design, low power dissipation and cost-effectiveness for large-scale production [12]. The structure of this circuit is compact and it can be mounted at the base station. It is essential to use highly accurate circuit element dimensions to ensure the Butler matrix performs excellently
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
