A design method for patch antennas with wide frequency tunable range and stable conical radiation

Conical beams have potential uses in wireless and satellite-based communication. In this study, we propose a method using a transmissive metasurface to achieve full control of the diverging effect of orbital angular momentum (OAM) modes to form the desired conical beam. A patch antenna functioning as the feed source is combined with the transmissive metasurface to enable the integration of the source and metasurface. For full control of conical radiation, including the cone angle and OAM mode, we introduce both radial and circumferential phase gradients to the proposed metasurface. Experiments are conducted in the microwave region to validate the design method, which shows good agreement with the simulation results. The proposed metasurface provides a means of flexibly generating conical beams with the designed OAM mode to assist potential applications in high-speed wireless communication.

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Highly omnidirectional and frequency tunable multilayer graphene-based monopole patch antennas

Journal of Materials Chemistry C ◽

10.1039/c9tc02454a ◽

2019 ◽

Vol 7 (26) ◽

pp. 7915-7921

Author(s):

Yun Ki Kim ◽

Yeri Lee ◽

Keun-Young Shin ◽

Jyongsik Jang

Keyword(s):

Carbon Nanotube ◽

Multilayer Graphene ◽

Patch Antennas ◽

Fabrication Method ◽

Multi Walled Carbon Nanotube ◽

Facile Fabrication ◽

Frequency Tunable ◽

Tunable Antennas

Highly omnidirectional and frequency tunable antennas based on multilayer graphene/multi-walled carbon nanotube electrodes were produced by a facile fabrication method.

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Characteristic Mode Theory of Wavetraps for Antenna Decoupling

10.36227/techrxiv.12509789 ◽

2020 ◽

Author(s):

Mikko Heino ◽

Clemens Icheln ◽

Pasi Ylä-Oijala ◽

Buon Kiong Lau ◽

Katsuyuki Haneda

Keyword(s):

Design Method ◽

Near Field ◽

Full Duplex ◽

Patch Antennas ◽

Duplex System ◽

Characteristic Mode ◽

Full Wave ◽

Receiving Antenna ◽

Operational Frequency ◽

Scattered Fields

This paper introduces a systematic design method for decoupling elements, which can significantly improve the isolation between two co-located antennas, e.g. between transmit and receive antennas of an in-band full-duplex system. The design method applies the theory of characteristic modes for controlling the phase and amplitude of the scattered fields of the decoupling element, in order to optimally cancel the original incident fields which couple to the receiving antenna. We describe concisely the effects that characteristic angle, modal near-field, and modal excitation of the decoupling element have on the antenna isolation. For validating the proposed method, a planar wavetrap is designed and the isolation improvement verified with full-wave simulations. When we use the proposed method to optimize a wavetrap that is placed between two co-located patch antennas, we obtain an improvement of the isolation between the antennas by 33 dB at the centre frequency of their operational frequency band, and at least 12-dB improvement across the whole 142-MHz operational bandwidth of the two antennas. As a benchmark, the wavetrap is replaced by an absorber occupying 10 times the volume of the wavetrap. The absorber gives only 6 dB of isolation improvement, substantiating the effectiveness of the proposed wavetrap method.

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Smart Cylindrical Dome Antenna Based on Active Frequency Selective Surface

International Journal of Antennas and Propagation ◽

10.1155/2017/5901625 ◽

2017 ◽

Vol 2017 ◽

pp. 1-14 ◽

Cited By ~ 2

Author(s):

Tongyu Ding ◽

Shaoqing Zhang ◽

Liang Zhang ◽

Yanhui Liu

Keyword(s):

Genetic Algorithm ◽

Mutual Coupling ◽

Angular Resolution ◽

Frequency Selective Surface ◽

High Gain ◽

Omnidirectional Antenna ◽

Tunable Range ◽

Frequency Tunable ◽

Frequency Selective ◽

Analytical Synthesis

In this paper, we proposed a beamforming antenna, which is realized using an omnidirectional antenna in the center surrounded by a cylindrical smart dome. The smart dome is made of 16 active frequency selective surface columns of which the amplitude and phase response can be continuously tuned by varying the bias voltages of the employed varactors. Thus, the performance of the proposed antenna could achieve higher gain, better nulling level, and more agility than many switch methods-based cylindrical reconfigurable antennas. Moreover, in order to overcome the unavailable analytical synthesis caused by complex mutual coupling between columns, we develop a genetic algorithm based optimization system and conducted a serial of experiments to evaluate the high-gain, nulling, continuously steering, and frequency-invariant ability. The results show that, during the frequency tunable range of the AFSS (2.0 GHz to 2.7 GHz), the antenna can offer an additional gain of up to 6.57 dB and nulling level of −56.41 dBi. For the high-gain modes, the −3 dB beam widths are 26°–34°, which offers enhanced angular resolution compared with other reported beam-sweeping work. Furthermore, the radiation pattern is continuously steerable.

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