With the demanding system requirements for the fifth-generation (5G) wireless communications and the severe spectrum shortage at conventional cellular frequencies, multibeam antenna systems operating in the millimeter-wave frequency bands have attracted a lot of research interest and have been actively investigated. They represent the key antenna technology for supporting a high data transmission rate, an improved signal-to-interference-plus-noise ratio, an increased spectral and energy efficiency, and versatile beam shaping, thereby holding a great promise in serving as the critical infrastructure for enabling beamforming and massive multiple-input multiple-output (MIMO) that boost the 5G. This paper provides an overview of the existing multibeam antenna technologies which include the passive multibeam antennas (MBAs) based on quasi-optical components and beamforming circuits, multibeam phased-array antennas enabled by various phase-shifting methods, and digital MBAs with different system architectures. Specifically, their principles of operation, design, and implementation, as well as a number of illustrative application examples are reviewed. Finally, the suitability of these MBAs for the future 5G massive MIMO wireless systems as well as the associated challenges is discussed.

Multibeam Antenna Technologies for 5G Wireless Communications

Resonance conditions for a substrate-superstrate printed antenna geometry which allow for large antenna gain are presented. Asymptotic formulas for gain, beamwidth, and bandwidth are given, and the bandwidth limitation of the method is discussed. The method is extended to produce narrow patterns about the horizon, and directive patterns at two different angles.

Gain enhancement methods for printed circuit antennas

By using a coplanar waveguide (CPW) feed with a widened tuning stub, a square slot antenna for broadband operation is presented. Experimental results show that the impedance matching for the proposed antenna strongly depends on the location of the tuning stub in the square slot, and the impedance bandwidth is mainly determined by the width and length of the tuning stub. By properly choosing the location and the size of the tuning stub, a wide impedance bandwidth of 60% can be obtained, which is about 1.9 times that of a conventional CPW-fed square slot antenna with a simple tuning stub. Details of the experimental results are presented and discussed.

Broadband CPW-fed square slot antennas with a widened tuning stub

Since their introduction by Kocher in 1998, power analysis attacks have attracted significant attention within the cryptographic community. While early works in the field mainly threatened the security of smart cards and simple processors, several recent publications have shown the vulnerability of hardware implementations as well. In particular, field programmable gate arrays are attractive options for hardware implementation of encryption algorithms,but their security against power analysis is a serious concern, as we discuss in this paper. For this purpose, we present recent results of attacks attempted against standard encryption algorithms, provide a theoretical estimation of these attacks based on simple statistical parameters and evaluate the cost and security of different possible countermeasures.

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An Overview of Power Analysis Attacks Against Field Programmable Gate Arrays

A wideband directional antenna composed of a shorted bowtie patch antenna and an electric dipole is presented. Through this composition, an equivalent magnetic dipole due to the shorted bowtie patch antenna and an electric dipole are excited together. Almost equal radiation pattern in the E- and H-planes is obtained. The proposed antenna has a wide impedance bandwidth, which is over 60% for SWR. < 2 ranging from 2.16-4.13 GHz.

Wideband Shorted Bowtie Patch Antenna With Electric Dipole

This paper presents simple (SEMA) and differential (DEMA) electromagnetic analysis attacks on an FPGA implementation of an elliptic curve processor Elliptic curve cryptography is a public key cryptosystem that is becoming increasingly popular Implementations of cryptographic algorithms should not only be fast, compact and power efficient, but they should also resist side channel attacks One of the side channels is the electromagnetic radiation out of an integrated circuit Hence it is very important to assess the vulnerability of implementations of cryptosystems against these attacks A SEMA attack on an unprotected implementation can find all the key bits with only one measurement We also describe a DEMA attack on an improved implementation and demonstrate that a correlation analysis requires 1000 measurements to find the key bits

Electromagnetic Analysis Attack on an FPGA Implementation of an Elliptic Curve Cryptosystem

A bow-tie slot antenna fed by CPW is introduced. It is designed to work in the Ku- band around 15.5 GHz. The proposed antenna is analysed both theoretically and experimentally. The presented results include the return loss and the radiation patterns. Two different geometries of the bow-tie antenna are presented and compared. The proposed antenna has several advantages such as a very large bandwidth, good control of its input impedance, and ease of fabrication. The proposed antenna has a dipole like radiation pattern which makes it suitable for mobile communication systems designed to work in the Ku- band.

Bow-tie slot antenna fed by CPW

We report on the design and measurement of an eight-by-eight modular phased array that uses analog quadrature baseband phase shifters. The array is designed for 2.4 GHz and has a few MHz of bandwidth. Though for such frequency, bandwidth and number of elements, digital beam forming is still feasible with contemporary analog-to-digital converters (ADC), the design is a proof of concept for analog baseband beam forming and shows that this technique will work at frequencies and bandwidths beyond ADCs capabilities. Besides covering the architecture, implementation and the measurement of the array, the calibration is discussed extensively, as this is an inevitable step in activating the antenna.

Conceptual Study of Analog Baseband Beam Forming: Design and Measurement of an Eight-by-Eight Phased Array

A dielectric superstrate with a high permittivity can be used to enhance the gain of a microstrip antenna. The effect of the superstrate is investigated experimentally in the case of a probe fed microstrip patch antenna. The measured radiation properties of the antenna structure are discussed in terms of an increasing spacing between the patch and the superstrate. The well known theoretical resonance conditions are clearly illustrated. The phenomenon of the splitting of the main beam is observed.

Peter Delmotte

Papers

Electromagnetic Analysis Attack on an FPGA Implementation of an Elliptic Curve Cryptosystem

Bow-tie slot antenna fed by CPW

Conceptual Study of Analog Baseband Beam Forming: Design and Measurement of an Eight-by-Eight Phased Array

Effect of superstrate on radiated field of probe fed microstrip patch antenna

Enhancing the gain of microstrip antennas at different frequencies with one substrate-superstrate structure