This letter describes a simple beam-tilting technique for an end-fire antenna using only a single-layer Frequency Selective Surface (FSS). The proposed approach is based on placing a parasitic FSS element under the antenna to tilt the beam in the desired direction. This is achieved by using a modified uniplanar compact FSS (MUC-FSS). To demonstrate the principle, the periodic structure is applied to a Yagi-Uda antenna operating in the millimeter-wave frequency band from 28 to 31 GHz. The measured results, by integrating the proposed FSS (1 layer of 3x5 unit cells) under the directors of the antenna, show that at 30 GHz, the main beam radiation tilts the end-fire direction (YZ plane) by +23° and -29° when the FSS structure is rotated by 90°, respectively. The simplicity of this method makes it suitable for 5G communication networks.

This letter presents a new design of tilted-beam antenna with gain enhancement based on the multilayer frequency selective surfaces (FSSs) for fifth-generation applications. A dual-sided printed FSS element with two C-shaped resonators at the top layer and a slotted circular patch at the bottom side, is proposed. The FSS element holds a size of 0.46λ × 0.46λ (at 28 GHz). A wideband Vivaldi antenna with an end-fire radiation is used to excite the elements of the FSS layers. The effects of different sizes, number, and the angular rotation of the FSS layers are employed to achieve the best antenna performance in terms of beam-tilting, realized gain, and reducing the sidelobe level (SLL). The best antenna performance is achieved when two unequal-sized FSS layers rotated to 45° and fixed under the Vivaldi. The proposed antenna is fabricated and measured. The obtained measured results show a maximum beam tilt angle of 38°, realized gain of 9 dBi, and SLL at –8 dB. The beam tilt angles are validated with the results obtained using the Snell's law in a multilayer environment and found a good agreement.

In this paper, a novel methodology using electrotextile fabrics is employed for designing a highly transparent, wideband frequency selective surface (FSS) in the millimeter-wave (MM-wave) band. The standard metallization is replaced by a low cost, extremely fine conductive mesh (RadioScreen or VeilShield) that gives to the periodic structure high see-trough properties in the 27-35 GHz frequency band. An acrylic dielectric material that is easily available and very low cost has been used as a substrate. Simulation and measurement results alike are presented to validate the principle. By assessing the high transparency properties of the FSS and its high performance in terms of stop-band, this FSS could be seen as a potential candidate for multiple 5G applications like for on-chip shielding, autonomous vehicles, antenna and on-chip antenna devices, radar cross section (RCS) augmentation, robotic guided paths and electromagnetic interference (EMI) protection.

A novel circular polarized dielectric antenna array (DRA) for millimeter-wave applications at 30 GHz is presented in this paper. The unit element array is a flower-shaped DRA fed with a cross slot. To obtain circular polarization, a sequential network combined with the cross slots is used to feed the $2\times 2$ array. The prototype of the proposed antenna array is fabricated and measured to obtain a wide resonance bandwidth from 27 GHz to 38 GHz frequency band. Furthermore, this left-hand polarized antenna array has achieved a peak gain of 9.5 dBi with 3-dB axial ratio at 30 GHz. The proposed DRA array with wideband resonance and gain bandwidth has the potential to be used for millimeter-wave wireless communications at the 30 GHz band.

A new corner-reflector antenna with a tunable gain based on active frequency selective surfaces (AFSSs) is presented. The proposed design comprises a dipole antenna as a source of the electromagnetic (EM) waves, and three reconfigurable AFSS layers of different size arranged at the same side of the dipole. Each screen consists of two AFSS panels that connected in series and rotated towards the feed to form a V-shaped corner reflector. These AFSS layers are mainly used to control the transmission/ reflection characteristics of the proposed antenna. By applying different combinations for ON/OFF states of diodes, the proposed antenna can adjust its gain value. The antenna performance in terms of reflection coefficient, radiation pattern in the H-plane and gain is analyzed at 5.8 GHz. To validate the concept of the proposed antenna, the prototype of the proposed antenna is fabricated and measured. The measured results show a good agreement with the simulated ones.

A circular polarized patch antenna for UHF RFID tag-based sensor applications is presented, with the circular polarization (CP) generated by a new antenna shape, an asymmetric stars shaped slotted microstrip patch antenna (CP-ASSSMP). Four stars etched on the patch allow the antenna’s size to be reduced by close to 20%. The proposed antenna is matched with two RFID chips via inductive-loop matching. The first chip is connected to a resistive sensor and acts as a sensor node, and the second is used as a reference node. The proposed antenna is used for two targets, serving as both reference and sensor simultaneously, thereby eliminating the need for a second antenna. Its reader can read the RFID chips at any orientation of the tag due to the CP. The measured reading range is about 25 m with mismatch polarization. The operating frequency band is 902–929 MHz for the two ports, which is covered by the US RFID band, and the axial-ratio bandwidth is about 7 MHz. In addition, the reader can also detect temperature, based on the minimum difference in the power required by the reference and sensor.