Active antenna

About: Active antenna is a research topic. Over the lifetime, 2246 publications have been published within this topic receiving 26493 citations.

Design actuation and control of active patch antennas

Abstract: The major drawback of a microstrip patch antenna is it's narrow bandwidth characteristics. One method that has been investigated to increase bandwidth is the addition of a parasitic element to the microstrip patch antenna. In an active microstrip patch antenna, variable bandwidth can be achieved by varying the spacing between the antenna and the parasitic element, which is fixed to a dielectric plate. In this study, an actuator is developed, tested and employed on an actual microstrip patch antenna and it's parasite. Since a relatively large displacement (1 cm) is needed, this mesoscale actuator is comprised of stacked Rainbow actuators. This study takes advantage of the fact that, for antennas operating at higher frequencies, smaller absolute displacements will result in significant percentage changes in antenna bandwidth. The use of the parasite and the active system accounted for up to a factor of five increase in antenna bandwidth. Various control techniques were employed to counteract the effects of hysteresis and creep on the actuator. Because the use of metal components can degrade antenna performance, emphasis was placed on synergy in the design process.

Active antenna structure maximizing aperture and anchoring RF behavior

Abstract: An antenna methodology where a set of antennas are formed that take the shape of a mobile wireless device and can be integrated into the outer housing of the mobile device Tuning points are integrated into the design to provide the capability to compensate for hand effects and loading while the mobile device and antenna are touched by the user The body then becomes a part of the antenna and acts as an anchor for the poles within the matching circuit These antennas are actively tuned based on detection criteria while dynamically tracking system performance The structure is based on a loaded loop coupled to an isolated magnetic dipole (IMD) element The loop is actively tuned according to design rules residing in a processor in the mobile device

Analysis of a two-port aperture-coupled microstrip antenna

Abstract: A two-port microstrip antenna is investigated by the method of moment. The antenna is a two-layer structure. The field coming from one microstrip line on the circuit layer is fed into the patch through an aperture on the ground plane. Part of the field is then coupled back to a second microstrip line through another aperture on the same ground. This configuration serves not only as a radiator but also as a feedback resonator, which is useful in designing an active antenna with a broad injection-locking bandwidth. Numerical results together with some measurements are illustrated and discussed.

Intelligent skin antenna capable of self-adaptively changing radiation and scattering characteristics

Abstract: The invention discloses an intelligent skin antenna capable of self-adaptively changing radiation and scattering characteristics, and aims to provide an intelligent skin antenna, which is capable of perceiving an external electromagnetic environment, and adjusting and controlling radiation/scattering characteristics in real time. The scheme in the invention is as follows: a Wearable sensor sends the fact that a radar wave monitoring result exists or not to a single chip microcomputer control unit through a multifunctional device; the single chip microcomputer control unit judges the radiation/scattering mode according to the TTL high and low levels of the address code corresponding to each channel of the multifunctional device; the radiation/scattering performances of the antenna are re-distributed according to requirements; furthermore, a power supply is controlled to apply different voltage values on a polyaniline conductive polymer, so that grading absorption of wave-transmitting radiation or radar wave of the intelligent skin antenna is obtained; in the radiation mode, a weight value obtained through a cloud genetic algorithm in advance is calculated into an amplitude/phase control code, and sent to an active antenna array, so that the low-sidelobe needle beam is realized; in the scattering mode, different voltage values are applied on an electrochromic skin wave-transmitting layer, so that wave absorption is realized; and the low interception probability and the low observable characteristic can be realized self-adaptively.