The frequency spectrum is congested due to usage on the part of many communication systems and a few radar and military systems. Most communication systems are half-duplex and they use separate bands or time slots to transmit and receive signals. This leads to underutilization of available resources and inefficient flow of information between wireless systems. Physical separation between the transmitter and receiver, with electromagnetic shielding or attenuation material placed in-between, can lead to their simultaneous operation in time and frequency; however, additional required space is often not available.

On the other hand, in-band full-duplex systems that transmit and receive simultaneously in the same frequency band overcome some of these issues. These systems, also known as simultaneous transmit and receive (STAR) systems, have potential to increase spectral efficiency by either doubling the number of users or by doubling the communication channel capacity for each user in the same frequency interval allocated for half-duplex communications.

However, the implementation of in-band full-duplex systems is challenged by self-interference between the strong transmitted and the weak received signal at each transceiver device. The higher transmitted power and narrower communication channel the greater are the isolation requirements, in some cases more than 150 dB. Moreover, wideband self-interference cancellation is more challenging than narrowband designs, leaving significant rooms for research before modern wideband radio communications can take full advantage of in-band full-duplex radios.

The prevailing thought is that the solution to the self-interference challenge is the combination among several approaches including: (i) antenna design; (ii) analog cancellation, for example through RF frontend design as its wider dynamic range and sensitivity is of crucial importance ; (iii) digital cancellation; In the context of STAR systems with maximum utilization of resources, applying one of these approaches is not sufficient to achieve the level of self-interference cancellation that leads to a workable system.

Moreover, the antenna subsystem design with co-channel self-interference reduction is required to ensure the low noise amplifiers and other actives in the chain do not overload. In this special issue, we consider novel contributions to self-interference cancellation that are based on antenna subsystem design and allow for the first level of cancellation in in-band full-duplex systems. We also gather new experimental evidences and models that explain them, based on extensive field tests of antenna systems along with physical and mathematical modeling of self-interference channels.

The purpose of this special issue is to draw attention to the latest progress in the understanding, development, and in-field deployment of antenna systems for in-band full-duplex applications. Contributions are sought for, but not limited to the following:

• Both single antenna configurations and multi-antenna systems across frequency spectrum of interest for current and future narrow-and wide-bandwidth RF systems.
• Advancements in novel techniques to integrate antennas and non-reciprocal devices or beamformers, use of novel materials and symmetries for improved self-interference cancellation.
• New configurations and techniques for in-band full-duplex phased arrays and switched beam antennas.
• Novel techniques for improved self-interference cancellation relying on polarization, space or beam multiplexing with major advancement in theory, experimental tests or demonstration in practical application scenarios.
• Measurements of in-band full-duplex antenna subsystems, tolerance analysis, multi-physics analysis and co-design, platform effects inclusive of design for immunity to the host structure, use of STAR for other purposes than communications, MIMO in-band full-duplex antennas.

Guest Co-Editors:

Danilo Erricolo
University of Illinois at Chicago, Chicago, IL, USA , This email address is being protected from spambots. You need JavaScript enabled to view it.;

Dejan Filipovic
University of Colorado at Boulder, Boulder, CO, USA, This email address is being protected from spambots. You need JavaScript enabled to view it.;

Haneda Katsuyuki
Aalto University, Finland, This email address is being protected from spambots. You need JavaScript enabled to view it.;

Zhijun Zhang
Tsinghua University, China, This email address is being protected from spambots. You need JavaScript enabled to view it..

Deadlines

Paper Submission: Oct. 31, 2020;
Publication Date: Aug. 2021.