In this paper, a new dense dielectric (DD) patch array antenna prototype operating at 28 GHz for future fifth generation (5G) cellular networks is presented. This array antenna is proposed and designed with a standard printed circuit board process to be suitable for integration with radio frequency/microwave circuitry. The proposed structure employs four circular-shaped DD patch radiator antenna elements fed by a 1-to-4 Wilkinson power divider. To improve the array radiation characteristics, a ground structure based on a compact uniplanar electromagnetic bandgap unit cell has been used. The DD patch shows better radiation and total efficiencies compared with the metallic patch radiator. For further gain improvement, a dielectric layer of a superstrate is applied above the array antenna. The measured impedance bandwidth of the proposed array antenna ranges from 27 to beyond 32 GHz for a reflection coefficient (S11) of less than -10 dB. The proposed design exhibits stable radiation patterns over the whole frequency band of interest, with a total realized gain more than 16 dBi. Due to the remarkable performance of the proposed array, it can be considered as a good candidate for 5G communication applications.

A high-gain slot-coupled circular patch antenna with a surface-mounted conical horn for millimeter-wave (MMW) applications at 31 GHz is proposed. The design adopts microstrip/conical horn hybrid technology for a 6-dB enhancement over the conventional circular patch antenna. The overall antenna gain is about 12 dB, which makes it suitable for MMW imaging applications and short-range communications. A slot feeding mechanism is used for exciting the microstrip patch dominant mode TM₀₁₀. The proposed design has been verified by simulations and finally confirmed by measurements.

In this article, a four-element dual-band printed slot antenna array for the future fifth generation (5G) mobile networks is proposed. The antenna element has a compact with size of 0.8 λ ₀ × 0.75 λ ₀ at 28 GHz. The simulated results show that the designed antenna has a dual-band function at 28/38 GHz that covers future 5G applications. The designed 1-to-4 modified Wilkinson power divider is used to feed the proposed array. For further enhancement of the designed power divider, an electromagnetic bandgap (EBG) structures are used. The proposed antenna array provides directional patterns, relatively flat gain, and high radiation efficiency through the frequency band excluding the rejected band.

An antenna sensor for millimeter wave (MMW) hidden target detection and warning applications is introduced. The sensor consists of three adjacent high gain microstrip/horn hybrid antenna elements. The central antenna acts as bi-static radar, while the two side antennas are used to receive the scattered back signals from a hidden object. The proposed antenna sensor has been employed in a detection/imaging system prototype based on time domain reflectometry (TDR). A very short pulse generated by a vector network analyzer is used to illuminate a three layers body model made from cotton, natural leather and reinforced papers. The model construction is chosen to emulate the presence of human body. Experimental scanning of a hidden metallic target has been conducted for three different orientations of the target. Compared to a single antenna sensor, the triple sensor shows a great enhancement in the detection ability and the constructed image resolution of a hidden target.

In the past decade, the majority of the launched satellites have a weight exceeds 1 Ton. Its development takes a long time, high cost, and has a large risk of failure, and does not allow for testing new technologies to avoid the mission's failure. From these points of view, space-tested technologies were preferred to mitigate the risk of failure. Our goal is to build and test our own S-band communication subsystem for CubeSat. The system should be developed with reliable and compact hardware and flexible and efficient software. It consists of passive components such as the antennas and the filters and other active components. The passive components are designed, fabricated and measured while the active components are based on commercial components. In this paper, two antenna boards are designed; one board faces the earth and the other board lies on the opposite side. Each board has two antennas; transmitter and receiver antennas. The transmitter/receiver antennas are operating in the downlink /uplink at frequency bands from 2.2 GHz to 2.29 GHz and from 2.025 GHz to 2.11 GHz, respectively. This configuration keeps the communication between the CubeSat and the ground station to facilitate the de-tumbling process of the CubeSat. The second component is the filters that separate the transmitter from the receiver. The two filters have high roll off and narrow fractional bandwidth within a compact area. The transceiver system is based on the analog devices chip AD9361 controlled by zynq-7000 FPGA. The output RF signal is amplified to approach 33dBm output power to the antenna port via QORVO chip that operates in the range from 700MHz to 2700MHz. The antennas and filters are fabricated and tested where good results are noticed so that they are ready for integrating with the whole CubeSat communication subsystem.

In this paper, the authors present a novel DRA/microstrip hybrid high gain and circularly polarized antenna for MMW applications. It consists of a printed rectangular patch with a shaped corners and a hollow rectangular DR radiator works together as a single antenna element fed by a rectangular aperture in the ground plane.