Search

Joint Communication and radio Sensing (JC&S) has gained significant attention over the past few years. The advantages of this technology include reduced cost, size and power consumption. With further advancements in JC&S systems, it can potentially be used in next-generation cellular networks, internet-of-things and upcoming applications such as Industry 4.0, where a single system is capable of performing a wide variety of functions or tasks. The inclusion of this technology will result in improved performance and safety of the systems. Even though communication and radio sensing make use of a similar Radio Frequency (RF) front-end, the specifications for both these technologies mainly differ in terms of bandwidth and linearity. In this survey, a detailed study of the specifications of radar and communication systems was conducted. For the RF front-end to operate efficiently in both radar and communication modes, there must be reconfigurability in terms of frequency, bandwidth, gain and linearity. In this survey, we investigated different frequency, bandwidth, gain and linearity reconfigurable low noise amplifier (LNA) and down-conversion mixer architectures. The merits and demerits of each architecture are discussed and a summary of the performance of the reconfigurable LNAs and down-conversion mixers in the literature is presented. Finally, possible topologies for JC&S are deduced based on their performance.

A novel dual-port multiple-input-multiple-output (MIMO) antenna arrangement is introduced for attaining quasi-omnidirectional circular polarization (OCP) towards device-to-device (D2D) integrated sensing and communications (ISAC) deployment in sixth generation (6G) networks. The antenna architecture comprises of three dielectric laminates arranged one below/above the other with each substrate juxtaposed to its counterpart by the air cavity. The upper laminate encompasses solitary element frequency selective surface (FSS) etched on both fronts. Impedance matching transmission lines and partly reactive impedance surfaces (RIS) were printed on the top and bottom region of the middle substrate, respectively. The lower laminate features microstrip feed lines on the top side and semi ground planes on the bottom. The MIMO antenna was made up of two ports and fed through proximity coupling from the opposite ends of the middle substrate’s top surface to resonate with a −10 dB impedance bandwidth (I-BW) of $\sim $ 35%. The partial RIS enabled $>$ 20 dB of isolation between the ports while the air cavities between the laminates contributed to achieve a realized gain of $>$ 7 dBi. The antenna occupies $1.2\lambda \times 1.2\lambda $ footprint and $0.1\lambda $ height at 12 GHz to exhibit quasi-OCP in the azimuth plane with axial ratio (AR) of < 3 dB and efficiency of $>$ 90%. The envelope correlation coefficient (ECC), diversity gain, specific absorption rate (SAR), and power density (PD) at the band of interest were < 0.1, $\sim $ 10 dB, < 1.6 W/kg, and < 10 W/ $\text{m}^{2}$ , respectively. The results of the Ansys HFSS simulations and the measurements taken within the anechoic chamber exhibited good agreement. In contrast to state-of-the-art quasi-OCP antennas operating in the 12 GHz spectrum, the novelty of the proposed MIMO antenna includes a straightforward and compact configuration that is integrated synergistically to provide reasonably high gain and efficiency values.

Abstract The advancement of communication and radar systems has triggered the demand for in‐band full‐duplex (IBFD) operation. IBFD is regarded as one of the most outstanding technologies in terms of its ability to improve spectral efficiency and data rate. IBFD operation has the potential not only to enable communication or radar systems separately, but to help realising radar sensing and communication at the same time, known as Joint Communication and Sensing (JC&S) technology. In realisation of IBFD and JC&S systems, self‐interference (SI) is the key challenge for antenna designers. In this article, a comprehensive survey on SI reduction techniques in the antenna domain is provided and the advantages and disadvantages of each technique are studied. SI reduction techniques have been proposed separately but an elaborated review of relevant techniques with a comparative study has not been presented yet. For the first time, a systematic comparative study of different SI reduction techniques is graphically presented to cover a comparison based on isolation, gain, and impedance bandwidth in terms of before and after SI reduction techniques. Moreover, this study also explores how antenna isolation characteristics vary with respect to the thickness and the permittivity of the substrate without any SI reduction technique.

In this paper, a planar polarization independent resonant cavity antenna (RCA) is proposed to achieve higher gain with a single patch connection instead of using antenna arrays with additional feeding losses. The planar metasurface is based on sub-wavelength complementary circular metallic patches, which provide the same magnitude and phase response for both TE and TM polarized waves. In order to excite the metasurface, an aperture coupled antenna with a circular patch is used to make its integration easier with the metasurface. The proposed antenna design works from 8.97 GHz to 13.1 GHz with a measured 3dB gain bandwidth of 24.2% and it is used to increase the antenna’s gain from 8 dBi up to 14.67 dBi. The RCA achieves the measured bandwidths (input matching ¡-10 dB) above 4 GHz or 37.4%, among the highest reported in the literature with 2 layers.

This paper focuses on the topic of joint communication and radar sensing (JCRS) and its applications in the scope of upcoming sixth-generation (6G) technology. While the fifth-generation applications have reached the consumer market in the last few years, JCRS has been identified as one of the key technologies for next generation networks. The role of JCRS will vary, ranging from tasks such as radar coordination, context awareness for communication, enhanced security, increased availability, and improving the resilience and trustworthiness of future networks. In this work, the niche of JCRS technology in the future 6G ecosystem, as well as several potential applications, are discussed with a focus on RF hardware. The use of centimeter (cmWave) and millimeter (mmWave) frequency spectrums in the context of JCRS system implementation have been further elaborated. After presenting the near-term application scenarios, the circuit implementation perspectives are investigated in terms of radio frequency (RF) front-end architectures, antenna implementation, and phased arrays. Different communication and radar antenna options are compared, and the best candidates are identified. The packaging options are also presented. From circuit and system perspectives, link budget and self-interference cancellation (SIC) are highlighted. Furthermore, future directions including the next steps on the path to enabling JCRS technology are presented throughout this article. Prior works focused more on physical layers and network capabilities of JCRS systems, with less focus on hardware possibilities; to fill this gap, this article aims to contribute to this exciting research topic with a holistic review of RF hardware, highlighting the diversity of applications and the available technologies to tackle the near- and long-term needs of consumer applications.

Abstract The motivation for this study about Physical Layer Security comes from bridging the gap between the vast theory and a feasible implementation. We propose a Physical-Layer-Security Box as a system-level Box is a system-level solution, named PLS-Box, to solve the key exchange between two wireless communicating parties. The PLS-Box performs a novel key generation method named time-frequency filter-bank. The entropy of the radio channel is harvested via a filter-bank processing, and then turned into a reciprocal security key, at both ends. In this concept work, we also focus on several PLS open issues, such as radio-frequency imperfections and accessibility to the baseband communication modem. The goal is to show a wide applicability of our PLS-Box to actual wireless systems, paving the way for an evolution of existing schemes.

This paper presents reconfigurable RF integrated circuits (ICs) for a compact implementation of an intelligent RF front-end for multiband and multistandard applications. Reconfigurability has been addressed at each level starting from the basic elements to the RF blocks and the overall front-end architecture. An active resistor tunable from 400 to 1600Ω up to 10 GHz has been designed and an equivalent model has been extracted. A fully tunable active inductor using a tunable feedback resistor has been proposed that provides inductances between 0.1-15 nH with Q > 50 in the C-band. To demonstrate reconfigurability at the block level, voltage-controlled oscillators with very wide tuning ranges have been implemented in the C-band using the proposed active inductor, as well as using a switched-spiral resonator with capacitive tuning. The ICs have been implemented using 0.18-μm Si-CMOS and 0.18-μm SiGe-BiCMOS technologies. [ABSTRACT FROM AUTHOR]