Tiago Varum

Printed antenna for DSRC systems with omnidirectional circular polarization

Emerging vehicular communications are a key to combat several mobility issues, like road safety and efficiency. Dedicated short range communications (DSRC) is a wireless technology, operating at 5.9GHz, designed for automotive use. To operate, this technology has two types of devices, one for vehicles and another for roadside. This paper presents the design of an antenna for the vehicle unit of the DSRC system. High bandwidth, omnidirectional radiation pattern with circular polarization and reduced dimensions make this antenna particularly suitable for this application.

Nonuniform Broadband Circularly Polarized Antenna Array for Vehicular Communications

Road safety applications drive the development of vehicular communications as support to intelligent transport systems. The communications network necessary for this is supported by dedicated short-range communications (DSRC), which is based on roadside units (RSUs) and onboard units. In the RSU, the DSRC physical-layer standards, along with practical issues, require specific radiation patterns of the respective antenna, leading to the use of unusual arrays of antennas. This paper describes a new concept based on a binomial array structure, which simplifies the design of the antenna array while ensuring good performance. The new structure developed for this antenna enabled the design of a feed network using unbalanced power dividers in the same plane as that of the radiating elements, maintaining the favorable characteristics of microstrip antennas. The array thus obtained met the desired specification, in terms of a radiation pattern with a bandwidth greater than 1 GHz.

Printed antenna for on-board unit of a DSRC system

Vehicular communications, among vehicles and between vehicles and infrastructures are based on wireless communication technology known as dedicated short range communications (DSRC), which are in great development with the aim of reduce the traffic problems and improve the road safety. This study is based on the development of a solution to an antenna to be used in the mobile module, usually named On-Board Unit (OBU). The antenna should have characteristics that meet the requirements for new DSRC at 5.9GHz band in Europe. The proposed antenna is a printed monopole with a reduced size that presents an omnidirectional radiation pattern in the horizontal plane and allows communications independently of the direction of vehicles. The wide bandwidth obtained is to enough to encompass the other band for DSRC communications used in Europe, at 5.8GHz, and become more tolerant to manufacturing problems.

Circularly polarized microstrip antenna array for the Ka-band

The growing needs of higher transmission rates lead to the use of the Ka frequency bands and multi-beam technology, in the satellite communications, allowing more coverage. This fact leads to the need for the use of directive antennas and beamforming techniques to achieve a precise control of radiation pattern. This paper presents the design of a circularly polarized microstrip antenna array, at 29 GHz, suitable to satellite communications. The array will be a module part to develop an ample antenna array suitable to fulfill the satellite requirements, and feed with an electronic beamforming network.

Non-uniform microstrip antenna array for Rx DSRC communications

The urgent need to mitigate traffic problems such as accidents, road hazards, pollution and traffic jam have strongly driven the development of vehicular communications. DSRC (Dedicated Short Range Communications) is the technology of choice in vehicular communications, enabling real time information exchange among vehicles V2V (Vehicle-to-Vehicle) and between vehicles and infrastructure V2I (Vehicle-Infrastructure). This paper presents a receiving antenna for a single lane DSRC control unit. The antenna is a non-uniform array with five microstrip patches. The obtained beam width, bandwidth and circular polarization quality, among other characteristics, are compatible with the DSRC standards, making this antenna suitable for this application.

Compact Multilayer Yagi-Uda Based Antenna for IoT/5G Sensors

To increase the capacity and performance of communication systems, the new generation of mobile communications (5G) will use frequency bands in the mmWave region, where new challenges arise. These challenges can be partially overcome by using higher gain antennas, Multiple-Input Multiple-Output (MIMO), or beamforming techniques. Yagi-Uda antennas combine high gain with low cost and reduced size, and might result in compact and efficient antennas to be used in Internet of Thins (IoT) sensors. The design of a compact multilayer Yagi for IoT sensors is presented, operating at 24 GHz, and a comparative analysis with a planar printed version is shown. The stacked prototype reveals an improvement of the antenna’s main properties, achieving 10.9 dBi, 2 dBi more than the planar structure. In addition, the multilayer antenna shows larger bandwidth than the planar; 6.9 GHz compared with 4.42 GHz. The analysis conducted acknowledges the huge potential of these stacked structures for IoT applications, as an alternative to planar implementations.

Detect and Pointing Algorithms Performance for a 2D Adaptive Antenna Array

In recent decades, we have witnessed a great progress in wireless communications. The huge amount of data that users expect to access has required an effort to increase the capacity of wireless networks. The main limitation of these communication systems is the increasing interference between channels and multipath fading. Smart antennas technology has emerged, solving some of these problems and improving the performance of wireless networks. This chapter addresses a group of algorithms, directions of arrival (DOA) and beamforming, applied to planar antenna arrays. The algorithms are simulated, and their performance is evaluated in terms of runtime, accuracy and dependence with signal-to-noise ratio (SNR), applied to a smart antenna system.

Non-uniform microstrip antenna array for tolling using a single access lane

Over the last few years we have seen the progress of vehicular communications, as a way of development of the entire highway infrastructure, offering a set of new applications and functionalities to the users. The electronic collection for parking, tolls, gas stations, are some outcome of this technological development. This paper presents an antenna array according with the dedicated short range communications standards that rules the tolling applications, with the specific application in the access roads to highways. The radiation pattern with an innovative shape, combined with good wide operating band opens good perspectives for the application of this antenna in vehicular communications.

Non-Uniform Microstrip Antenna Array for DSRC in Single-Lane Structures

Vehicular communications have been subject to a great development in recent years, with multiple applications, such as electronic payments, improving the convenience and comfort of drivers. Its communication network is supported by dedicated short range communications (DSRC), a system composed of onboard units (OBU) and roadside units (RSU). A recently conceived different set-up for the tolling infrastructures consists of placing them in highway access roads, allowing a number of benefits over common gateway infrastructures, divided into several lanes and using complex systems. This paper presents an antenna array whose characteristics are according to the DSRC standards. Additionally, the array holds an innovative radiation pattern adjusted to the new approach requirements, with an almost uniform wide beamwidth along the road width, negligible side lobes, and operating in a significant bandwidth.

Cognitive bio-radar: The natural evolution of bio-signals measurement

In this article we discuss a novel approach to Bio-Radar, contactless measurement of bio-signals, called Cognitive Bio-Radar. This new approach implements the Bio-Radar in a Software Defined Radio (SDR) platform in order to obtain awareness of the environment where it operates. Due to this, the Cognitive Bio-Radar can adapt to its surroundings in order to have an intelligent usage of the radio frequency spectrum to improve its performance. In order to study the feasibility of such implementation, a SDR based Bio-Radar testbench was developed and evaluated. The prototype is shown to be able to acquire the heartbeat activity and the respiratory effort. The acquired data is compared with the acquisitions from a Biopac research data acquisition system, showing coherent results for both heartbeat and breathing rate.