Folded inverted conformal antenna

About: Folded inverted conformal antenna is a research topic. Over the lifetime, 4747 publications have been published within this topic receiving 68000 citations.

Reconfigurable Multiband Antenna Designs for Wireless Communication Devices

Abstract: New designs for compact reconfigurable antennas are introduced for mobile communication devices. The uniqueness of the antenna designs are that they allow various groups of their operating frequency bands to be selected electronically. In particular, each group of frequency bands, or mode, can be made to serve several different communication systems simultaneously. These systems may include various combinations of GSM, DCS, PCS, UMTS, Bluetooth, and wireless local-area network (LAN). Therefore, by electronically selecting different antenna modes, a variety of communication systems can be conveniently served by only one antenna. One advantage is that through the different operational modes, the total antenna volume can be reused, and therefore the overall antenna can be made compact. In these designs, the selection of the different modes is achieved by either i) switching different feeding locations of the antenna (switched feed) or ii) switching or breaking of the antenna's connection to the ground (switched ground). This paper demonstrates these two designs. For the first design of switched feed, it can support GSM, DCS, PCS, and UMTS. In the second design, the antenna makes use of a switched-ground technique, which can cover GSM, DCS, PCS, UMTS, Bluetooth, and 2.4 GHz wireless LAN. The designs are investigated when ideal switches and also various realistic active switches based on PIN diodes, GaAs field effect transistor, and MEMs configurations. The designs are verified through both numerical simulations and measurement of an experimental prototype. The results confirm good performance of the two multiband reconfigurable antenna designs.

A reconfigurable aperture antenna based on switched links between electrically small metallic patches

Abstract: A reconfigurable aperture (RECAP) antenna is described in which a planar array of electrically small, metallic patches are interconnected by switches. The antenna can be reconfigured to meet different performance goals by changing the switches that are open and closed. The switch configuration for a particular goal is determined using an optimizer, such as the genetic algorithm. First, the basic concept for the RECAP antenna is verified by comparing theoretical results with measurements for configurations in which the switches are simply wires connecting the patches. Next, details are given for a prototype antenna in which field-effect transistor based electronic switches are used with optical control. Theoretical results for the prototype antenna are then compared with measurements for cases in which electronic reconfiguration is used to change the bandwidth of operation or steer the pattern of the antenna. Finally, an overview of alternate switch/control strategies, some of which were tested, is given along with suggestions for improving the next generation of this antenna.

Small Square Monopole Antenna With Inverted T-Shaped Notch in the Ground Plane for UWB Application

Abstract: In this letter, we present a novel printed monopole antenna for ultrawideband (UWB) applications. The proposed antenna consists of a square radiating patch with two rectangular slots and a ground plane with inverted T-shaped notch, which provides a wide usable fractional bandwidth of more than 120% (3.1212.73 GHz). The proposed antenna is simple and small in size. Simulated and experimental results obtained for this antenna show that it exhibits good radiation behavior within the UWB frequency range.

A Dual-Band Inverted-F MIMO Antenna With Enhanced Isolation for WLAN Applications

Abstract: This letter presents a dual-band inverted-F multiple-input-multiple-output (MIMO) antenna with improved isolation, covering the 2.4/5-GHz wireless local networks (WLAN) band. The proposed MIMO antenna is composed of two symmetrical winding inverted-F antenna elements. The two antenna elements are closely spaced with about 0.115 λ 0 of the lower band. The high isolation is achieved by building two decoupling devices, a meandering resonant branch and an inverted T-shaped slot etched on the ground for the higher band and the lower band, respectively. Furthermore, two U-shaped slits achieving better impedance matching are etched on the 50-Ω feeding lines to broaden the bandwidth of the high band. The impedance bandwidth (S 11 <; -10 dB) of the proposed antenna covers 2.4-2.48 GHz in the lower band and 5.15-5.825 GHz in the upper band, and the proposed configuration obtains 15-dB isolation within the 2.4- and 5-GHz WLAN bands, which shows a significant improvement compared to the initial design of the MIMO antenna. The simulation and measurement results indicate that the proposed inverted-F MIMO antenna system is quite suitable for WLAN applications.

Characteristic Mode Based Tradeoff Analysis of Antenna-Chassis Interactions for Multiple Antenna Terminals

Abstract: The design of multiple antennas in compact mobile terminals is a significant challenge, due to both practical and fundamental design tradeoffs. In this paper, fundamental antenna design tradeoffs of multiple antenna terminals are presented in the framework of characteristic mode analysis. In particular, interactions between the antenna elements and the characteristic modes and their impact on design tradeoffs are investigated in both theory and simulations. The results reveal that the characteristic modes play an important role in determining the optimal placement of antennas for low mutual coupling. Moreover, the ability of antenna elements to localize the excitation currents on the chassis can significantly influence the final performance. To demonstrate the effectiveness of the proposed approach, a dual-band, dual-antenna terminal is designed to provide an isolation of over 10 dB for the 900 MHz band without additional matching or decoupling structures. A tradeoff analysis of bandwidth, efficiency, effective diversity gain and capacity is performed over different antenna locations. Finally, three fabricated prototypes verify the simulation results for representative cases.