This paper presents a novel method to evaluate radiation energy and mutual coupling in multimode antennas. Based on the theory of characteristics mode, how much each mode occupies the radiation and the mutual coupling from each feeding port is calculated with the modal energy occupied coefficients. Furthermore, the linear transformation of feeding network in multimode antenna system has been adopted to complete the modal-based method. Then, this method is utilized to analyze and decrease the mutual coupling between feeding ports. Hence, a hexagonal wideband antenna is proposed with its evolution process and measured to validate the proposed method. The presented hexagonal antenna is a four-port multimode antenna consisting a planar hexagonal plate, vertical tapered baluns, and feeding network at the ground plane. The whole antenna works in 3-6 GHz and all its four ports are well matched with high port-to-port isolation.

Abstract-This paper presents a design of two compact, light, rigid and low-cost 3D-printed millimeter-wave antennas for 5G communication system. The proposed antennas consist of a radiating slot that is surrounded by a rectangular cavity and corrugations which boost the gain performance of the antennas. Furthermore, the proposed antennas are fabricated using 3Dprinting technology and they are metallized using novel, simple and low cost techniques which utilizes commercial conducive spray-coating technology. The proposed antennas operate at 28-GHz band, where the first design is fed by a waveguide to prove the performance, while the second design is fed by a microstrip line to demonstrate the ability to be integrated into a compact structure. Measurement results show a wide impedance bandwidth which enables the proposed antenna design to be a strong candidate for 5G applications.

No abstract

This paper presents designs and prototypes of low cost multiple input multiple output (MIMO) antennas for 5G and millimetre-wave (mm-wave) applications. The proposed MIMOs are fabricated using 3D printing and are able deliver beams in multiple directions that provide continuous and real time coverage in the elevation of up to ∓30 • without using phase shifters. This equips the proposed MIMO with a superior advantage of being an attractive low cost technology for 5G and mm-wave applications. The proposed MIMO antennas operate at the 28 GHz 5G band, with wide bandwidth performance exceeds 4 GHz and with beam switching ability of up to ∓30 • in the elevation plane. The direction of the main beam of the single element antenna in the MIMO is steered over the entire bandwidth through introducing 3D printed walls with different heights on the side of the 3D printed radiating antenna. Unlike all other available beam steering techniques; the proposed wall is not only able to change the direction of the beam of the antenna, but also it is able to increase the overall directivity and gain of the proposed antenna and MIMO at the same time over the entire bandwidth.

A subwavelength slot fed high gain and compact dual layer corrugated plate antenna is presented in this paper. The antenna is realized by placing a second corrugated layer on top of the traditional corrugated plate antenna. The addition of the second layer generates waves reflection that produces multi-resonance frequencies to improve the antenna's bandwidth. Compared to a traditional single layer corrugated plate antenna, the proposed dual layer antenna has higher gain, lower side lobe level, narrower half power beam width (HPBW) and better impedance bandwidth. A prototype of the proposed antenna is built and tested. It has a measured peak gain of 16.3 dB at 11.3 GHz and an impedance bandwidth of 27%. The operating principle of the proposed antenna is also discussed and analysed.