Reconfigurable Radiation Pattern Research Articles

Frequency and Radiation Pattern Reconfigurability of a Multi-Size Pixel Antenna

Pixel reconfigurable apertures constitute one of the most adaptable structures regarding antenna reconfiguration, being capable to achieve frequency and pattern compound reconfiguration. However, pixel antennas require a large amount of switches (typically above 100) that severely impact the antenna efficiency, complexity, cost and reconfiguration time. This paper presents a novel technique to mitigate the inherent complexity of pixel antennas by including multiple sized pixels divided over driven and parasitic regions. The technique has been applied to a planar monopole architecture leading to a low-complexity prototype of small dimensions and requiring only 12 switches. Its reconfiguration properties have been fully characterized through exhaustive measurements. Frequency reconfiguration is achieved from 1 GHz to 6 GHz with simultaneous beam-steering capabilities, being capable of synthesizing at each frequency an omnidirectional pattern and up to 5 directive patterns steered towards directions covering an angular range of almost 180°.

Compact and Multiband Dielectric Resonator Antenna With Pattern Diversity for Multistandard Mobile Handheld Devices

A compact multiband antenna system using a dielectric resonator antenna (DRA) is presented in this paper. Designed to be integrated in a tablet, it is not only heavily miniaturized (λ0/15×λ0/38×λ0/94 at 800 MHz), but also able to cover three frequency bands for different wireless applications (DVB-H, WiFi and WiMAX). Since a reconfigurable radiation pattern can result in an improved quality and reliability of wireless links, two DRAs have been integrated to implement this feature on the three frequency bands. These improvements are demonstrated by the presentation of the correlation coefficient and the effective diversity gain, both measured in a reverberation chamber. The experimental measurements are in very good agreement with the simulated ones. Good overall performances are obtained, and the requirements of all three applications are perfectly met. Moreover, the antenna operative frequencies are independent of the ground plane dimensions, making this system a very good candidate for all kinds of mobile devices.

Tridimensional Yagi antenna: shaping radiation pattern with a non-planar array

This work presents the concept and development of the tridimensional Yagi antenna, which is a novel type of Yagi antenna operating in P band. It is idealised from two other types of Yagi antennas: Quasi-Yagi and Yagi-Uda. The resultant antenna is based on a microstrip balun, as in the first, and its driver and directors are made from metal tubes, as in the second, both integrated to a reflecting plane. The key point of this new antenna model is its asymmetric and reconfigurable radiation pattern and therefore the possibility of a high rejection between sectors in a plane. This feature was accomplished with the new concept of progressive rotation of directors around the driver. The authors present a design methodology to adjust return loss and radiation pattern characteristics. The final prototype presents 9.4 dB gain at 450 MHz and 47% bandwidth centred at 425 MHz.

Frequency and Radiation Pattern Reconfigurable Small Metamaterial Antenna using its Extraordinary Zeroth-Order Resonance

A frequency and radiation pattern reconfigurable small metamaterial antenna is proposed. The antenna's size is reduced by using the zeroth-order resonance of the metamaterial. Furthermore, frequency reconfigurability is provided by the tuning slots. Since the electrical length of the slots determines the zeroth-order resonant frequency, tunability is achieved by placing pin diodes on the slots. It is experimentally demonstrated that the resonant frequency is changed from 2.32 GHz to 3.14 GHz. In addition, radiation pattern reconfigurability is obtained from tunable slots. The electrical dimension of the antenna is 0.09λg by 0.16λg at 2.32 GHz.

A Reconfigurable Radial Line Slot Array (RLSA) Antenna for Beam Shape and Broadside Application

A reconfigurable beam shape and broadside radiation pattern microstrip antenna is introduced in this paper. The antenna's radiating surface is designed using a radial line slot array (RLSA) arrangement, which is fed from an aperture coupled structure. This novel feeding structure for an RLSA antenna incorporates PIN diode switches which are integrated with the feed line structure to enable the various outcomes of the radiation patterns. The circular arrangement of slots at the radiating surface contributes to the reduction in size of the proposed antenna compared to conventional microstrip antenna that can yield the same antenna gain. The proposed antenna design operates at 2.3 GHz frequency band and has a maximum gain of 14.64 dB. It also produces a broadside radiation pattern with a wider beamwidth covering from −85° to 85° compared to the conventional microstrip antenna which could only cover from −50° to 50°. The proposed antenna has an enormous potential for point-to-point and point-to-multipoint communication, WiMAX, and radar application.

Switchable Printed Yagi-Uda Antenna with Pattern Reconfiguration

A switchable Yagi-Uda antenna prototype with radiation pattern reconfiguration is presented in this letter. The proposed reconfigurable antenna is based on the concept of switching between the reflector and director of a Yagi-Uda antenna using a radio frequency PIN diode. As a result, the minimum/maximum radiation can be steered towards desired signals or away from interfering signals in opposite directions. The measured 10 dB impedance bandwidth and gain are 210 MHz (7%) and 8.02 dBi at 3 GHz, respectively. Details of the antenna design and its performance are described and empirically analyzed.

A Wideband Slotted Bow-Tie Antenna With Reconfigurable CPW-to-Slotline Transition for Pattern Diversity

We propose a slotted bow-tie antenna with pattern reconfigurability. The antenna consists of a coplanar waveguide (CPW) input, a pair of reconfigurable CPW-to-slotline transitions, a pair of Vivaldi-shaped radiating tapered slots, and four PIN diodes for reconfigurability. With suitable arrangement of the bias network, the proposed antenna demonstrates reconfigurable radiation patterns in the frequency range from 3.5 to 6.5 GHz in three states: a broadside radiation with fairly omnidirectional pattern and two end-fire radiations whose main beams are directed to exactly opposite directions. The proposed antenna is investigated comprehensively with the help of the radiation patterns in the two principal cuts and also the antenna gain responses versus frequencies. The simulation and measurement results reveal fairly good agreement and hence sustain the reconfigurability of the proposed design.

A Wideband L-Probes Fed Circularly-Polarized Reconfigurable Microstrip Patch Antenna

A wideband circularly polarized reconfigurable microstrip patch antenna fed by L-shaped probes is presented. Right hand circular polarization and left hand circular polarization could be excited by L-shaped probes feeding a perturbed square patch. The L-shaped probes are connected to a switch which is fabricated underneath the ground plane, such that circularly polarized radiation pattern reconfiguration could be realized. An antenna prototype was fabricated and it attains a bandwidth of over 10% with both SWR < 2 and axial ratio < 3 dB.

Fractal Hilbert microstrip antennas with reconfigurable radiation patterns

AbstractThis paper presents two novel pattern reconfigurable microstrip antennas, which are formed by second‐ and third‐order fractal Hilbert curves, respectively. Both of the antennas have the feature of linearly polarized reconfigurable radiation patterns. By controlling switches on/off, the radiation patterns can be reconfigured in the upper‐half space. The two antennas have potential applications in mobile communication systems and large phased arrays. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 352–354, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22122