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This paper presents the design of a meander printed monopole antenna dedicated for cognitive radio on mobile devices. The proposed antenna structure is able to reconfigure its operating frequency while preserving its gain pattern characteristics over the different bands. The antenna operation is controlled through a built-in graphical user interface. The interface can control the antenna based on...
This paper presents a new radio frequency (RF) rectifying design that is based on a tapered matching network. The rectifier operates over the Wi-Fi 802.11 b/g bands. The tapered matching network aims at transforming the Schottky diode's impedance into the input impedance of the circuit by resorting to dual transmission lines. Each line is designed with a different characteristic impedance. The rectifier...
In this paper, a reconfigurable patch antenna design operating at 868MHz for Low Power Wide Area Network (LoRa), 1.58 GHz for Global Positioning System (GPS) and 2.4 GHz for Bluetooth is presented. The design is reconfigurable thanks to the integration of a digitally tunable capacitor (DTC). The DTC capacitance changes according to a 5 bits' sequence command. A microcontroller is used to assign the...
In this communication, a frequency and pattern reconfigurable V–shaped printed antenna is presented. The proposed structure operates at two different frequency bands. The variation in the frequency of operation is achieved by individually extending the length of each of the two antenna arms. The directional behavior of the proposed antenna structure is improved through the incorporation of a triangular...
This paper focuses on enhancing multiband isolation between two antenna elements in a reconfigurable multiple input multiple output (MIMO) system. The antennas are reconfigurable printed inverted F antennas (PIFA) that resort to two PIN diodes each to achieve frequency reconfiguration. The isolation between the antenna elements is proposed to be improved through the use of multiple nested slots in...
This paper presents the design of a 3D printed quadrifilar helix antenna. The antenna is miniaturized by loading the tip of each helix by metallic circles of equal dimensions. The effect of decreasing the resonant frequency is also achieved by introducing a dielectric material within the antenna's physical structure. A prototype is fabricated and tested to prove the proposed technique. A good agreement...
In this paper, a new reliable radio frequency (RF) rectifier topology with an enhanced operating power range is proposed. The presented RF harvester possesses an efficient RF to DC conversion ratio over an enhanced power range. A typical RF rectifier is initially optimized, and then the RF input is equally split into two branches. Splitting the input RF power improved the reliability and breakdown...
This paper presents the design of two antenna structures that are proposed for implementation in a cognitive radio environment. Such designs are software controlled and suitable for operation in a highly dynamic environment. The reconfiguration and automation of the two structures are discussed herein. The incorporation of such antenna structures on a software defined radio (SDR) platform is also...
In this paper, two compact multiband and reconfigurable planar inverted-F antenna (PIFA) designs operating at GPS, 3G, WiFi, GSM and 4G (UMTS and LTE) frequencies are presented. The multiband operation is accomplished by the multi-resonant slots while the reconfigurable PIFA operation is based on the appropriate integration of PIN diodes switches. Both antennas are proposed as suitable candidates...
This paper proposes a new RF rectifier with a dynamically extendable RF-DC power conversion (> 50%) range. Compared to typical rectifiers, the adopted power combining topology extends the dynamic efficient range by ∼ 3 dB, while maintaining acceptable performance at low powers. A 1.84 GHz rectifier with the proposed topology is designed. A prototype of the designed rectifier is fabricated and tested...
This paper discusses various deployable antenna designs that are proposed for CubeSat platforms. The antennas discussed vary in their topology and structure from arrays of crossed dipoles to helical structures. Several concepts are presented and their performance is described and evaluated.
The implementation of a four sectorial reconfigurable MIMO antenna system is discussed in this paper. The proposed antenna system consists of two MIMO structures that operate at two different frequencies. The reconfigurability of the antenna system is software controlled through an arduino board and a mobile phone application. A prototype is fabricated and tested as a proof of concept.
A Liquid Crystal (LC) based reconfigurable antenna array design at W/V-band is presented in this paper. The array exhibits both frequency tuning and beam steering due to the dielectric anisotropy of the LC at microwave frequencies. The design of the array is optimized to ensure reconfiguration while having the least number of connections to DC sources. The array is fed using a Grounded Coplanar Waveguide...
In this paper, a reconfigurable cognitive radio receiver for autonomous spectrum sensing is presented. A reconfigurable antenna, low-noise amplifier, reconfigurable bandpass filter, single-ended balanced mixer, voltage-controlled oscillator (VCO), and variable gain amplifier (VGA) build up the chain of the proposed receiver. This receiver targets the WLAN IEEE 802.11WLAN IEEE 802.11 g commercial wireless...
This paper presents a new antenna system that reconfigures its radiation pattern through feed rotation. The radiation pattern reconfiguration allows a better Wireless LAN coverage through a personalized command by resorting to an Android phone application and an Arduino microcontroller.
Recent advances in reconfigurable RF components and systems have helped in the development of very complex reconfigurable antennas capable of radiating more than one pattern at different frequencies and polarizations. These types of antennas are becoming critical components in modern telecommunication systems from cognitive radio to cubesat communications.
In this paper, a varactor-tuned filter-antenna (filtenna), for cognitive radio applications is proposed. The presented technique is based on electronically tuning the resonant frequency of a compact tunable band-pass filter, which is integrated into a wideband antenna. The change in the loading capacitance of the installed varactor results in frequency tuning of the whole filtenna system, while preserving...
This paper discusses the integration of an inverted- F antenna with solar cells for power harvesting. The objective is to achieve a multi-source energy collecting system in order to improve the RF to DC conversion efficiency. The inverted-F antenna can be used either for communication or to scavenge the ambient RF energy when connected to the appropriate rectifying circuit. A prototype of the antenna...
This paper describes the implementation of an efficient transparent log spiral antenna for energy harvesting. The proposed antenna is a wide band antenna with circular polarization which is integrated with solar panels. The goal is to implement an efficient technique to collect RF energy without degrading the performance of the solar cell.
This paper discusses the design of a new conical log spiral antenna that can operate at UHF frequencies. The antenna constitutes a suitable candidate for deployment on top of a 6U CubeSat system. The conical log spiral is designed to operate between 300 MHz and 600 MHz and exhibit circular polarization as well as an acceptable gain. The antenna is also required to satisfy size constraints by being...
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