Plasma Antenna Array Research Articles

Experimental Investigation of a Photogenerated Silicon Plasma Monopole Antenna

This work investigates the photoconductive effect in high-resistivity silicon (HRS) as the radiating element of a plasma monopole antenna. A silicon chiplet forming the monopole is mounted on top of an antenna feed network patterned on a printed circuit board (PCB) substrate. By exciting the silicon chiplet with a light source supplied by optical fibers, the monopole can be changed from a dielectric to a conductor, thus making the antenna indistinguishable from typical substrates in the OFF-state and radiating in its ON-state. The experimental results show a peak broadside realized gain of −2.6 dBi at 16.9 GHz and an ON/OFF ratio greater than 17.8 dB from 14.2 to 20 GHz. The silicon plasma antenna is also shown to radiate between 43% and 62% of the broadside power in comparison to a fully copper monopole antenna with equivalent dimensions. The proposed photogenerated silicon plasma monopole antenna demonstrates significant potential as an antenna element for integration within a plasma antenna array system.

Experimental Study on a Self-Phase-Shifting Cross Vibrator Plasma Antenna Array

The study designs a type of plasma antenna array with four quartz fluorescent lamps, which can be classified into linear polarization and circular polarization (CP). The antenna arrays are designed into a self-phase-shifting cross shape, and the kHz alternating current power supplies are adopted in the proposed antenna arrays. Experimental results show that the cross vibrator antenna can realize not only impedance and pattern reconstruction, but also the polarization transformation. Moreover, the horizontal polarization, vertical polarization, and CP can be mutually transformed into each other by changing the vibrator operation mode. It is noted that we can easily transform the left-hand circular polarization and right-hand circular polarization into each other via modifying vibrator length and plasma density. Compared with a conventional metal antenna with the same shape, polarization conversion can be realized in an easier yet faster way via the help of self-phase-shifting plasma antenna array.

Plasma monopole antenna array

PurposeThis study aims to investigate different configurations of plasma antenna arrays and multiple combinations based on whether the plasma dischargers are set ON or OFF, to assess the coupling, interference and overall performance of these plasma antenna arrays.Design/methodology/approachIn this paper, the authors investigate the operation and performance of the combined use of sets of antennas and plasma antenna elements in plasma monopole antenna arrays.FindingsThe authors find that there can be significant modifications of the plasma antenna arrays’ gain and pattern in multiple ways, merely by switching different combinations of plasma columns ON and OFF.Originality/valueHigh-density plasma antenna arrays have been examined in this paper and it has been shown that they are capable of reaching high antenna gain. Moreover, the overall antenna array’s gain and pattern can be considerably transformed in multiple ways by turning ON and OFF different combinations of plasma antenna elements. Finally, the electromagnetic coupling and interference coming from these plasma antennas can be greatly reduced.

Development of Reconfigurable Plasma Column Antenna

The work presented in this article evaluates the radiation characteristic of the plasma antenna in its classical state called plasma striation. The plasma antenna is basically a plasma column coupled with an RF signal source. The experimental setup of the plasma antenna has been developed, which includes a plasma and vacuum system, the RF signal source along with the matching network, and an automated radiation measurement system to measure the radiation parameters. The radiation characteristics of the plasma antenna depend on the plasma properties, such as plasma length and plasma density, which are the functions of input RF power and gas pressure. In a column, a single length plasma can be transformed into multiple small striations or blobs by having a critical combination of applied power and pressure. In this experiment, radiation patterns of antenna have been measured for the variable plasma parameters and tuned frequencies. The study reveals that the typical arrangement of blobs forms a collinear plasma antenna array, where the radiation parameters can be reconfigured with the size, number, and spacing between blobs and plasma density. The study outcomes the present useful development in the area of reconfigurable RF antenna that is a research interest in the field of radar for beamsteering applications and communication.

Design and Fabrication of Plasma Yagi–Uda Array Antenna With Beamforming

In this paper, the design and implementation of a plasma antenna array using Yagi–Uda reflectors with beamforming is discussed. The structure consists of the circular array of plasma tubes enclosed a unipolar L-band monopole antenna. Beamforming is possible using stimulated plasma tubes. The combination of the above structure with plasma excitation controller provides smart beamforming and uses of the Yagi–Uda structure increases gain compared to previous models. An experimental model in the L-band is fabricated that shows a good agreement between simulated and measured results.

Beam‐forming capabilities of a plasma circular reflector antenna

A gaseous plasma antenna array (PAA) is an aggregate of plasma discharges and possibly conventional metallic radiating elements, and it constitutes a promising alternative to metallic antennas for applications in which fast reconfiguration of radiation pattern, and gain is desired; such properties can be achieved by exploiting the electronic switch on/off condition of plasma discharges, and tuning of the plasma parameters. Here, the authors present a reconfigurable PAA that features a central metallic half-wavelength dipole working around 1.45 GHz, surrounded by a planar circular lattice of cylindrical plasma discharges. Customised plasma discharges have been realised, and filled with argon gas at 2 mbar so as to have a complete control on the plasma discharge properties (e.g. plasma frequency, collisional frequency). The magnitude of the reflection coefficient, and the gain pattern on the H -plane have been investigated numerically and experimentally; numerical and experimental results exhibit a good agreement and show that the central intrinsically omnidirectional antenna can provide simple beamforming capabilities upon turning on a subset of plasma discharges; as these plasma discharges are turned on, the authors have observed a maximum gain of ~5 dBi, a half-power beam width of 80°, and an angular steering resolution of ~15°.

A novel reconfigurable radiating plasma antenna array based on Yagi antenna technology

An electronically controlled plasma reflector antenna array is presented in term of Yagi antenna technology and plasma theory in this paper. The array comprised of a plasma symmetrical dipole in the center and 6 plasma column antennas uniformly around the dipole. When only the active plasma dipole and one of passive columns are energized, they perform like conductive metals capable to radiate radio signal like a two-element plasma Yagi antenna. Pattern reconfigurability of the antenna array can be achieved by sequentially exciting one of 6 plasma columns, and the plasma antenna array also produces better gain through increasing the number of plasma reflectors. Due to the adoption of equal amplitude and phase feeding technology, it greatly reduces the technical difficulty of the implementation of pattern reconfigurability. On the other hand, if all of plasma columns are off, there is only minor reflection from dielectric tubes, and hence, the plasma antenna array has stealth performance.

Reconfigurable Plasma Antenna Array by Using Fluorescent Tube for Wi-Fi Application

This paper presents a new design of reconfigura- ble plasma antenna array using commercial fluorescent tube. A round shape reconfigurable plasma antenna array is proposed to collimate beam radiated by an omnidirec- tional antenna (monopole antenna) operating at 2.4 GHz in particular direction. The antenna design consists of a monopole antenna located at the center of a circular alu- minum ground. The monopole antenna is surrounded by a cylindrical shell of conducting plasma. The plasma shield consists of 12 commercial fluorescent tubes aligned in series containing a mixture of argon gas and mercury vapor which upon electrification forms plasma columns. The plasma behaves as a conductor and acts as a reflector in radiation, in the condition where plasma frequency, ωp is higher than the operating frequency. From this concepts, when all plasma elements are activated or switched to ON, the radiation signal from the monopole antenna will trapped inside the plasma blanket and meanwhile when one or more plasma elements is deactivated (switched OFF), the radiation from the monopole antenna will es- cape. This antenna has the capability to change its patterns with beam direction at 0°, 30°, 60°, 90°, 120°, 150°, 180°, 210°, 240°, 270°, 300° and 330° at frequency 2.4 GHz. The proposed antenna has been successfully fabricated and measured with conclusive results.

BEAM-FORMING AND BEAM-STEERING CAPABILITIES OF A RECONFIGURABLE PLASMA ANTENNA ARRAY

We present the numerical parametric study of a reconfigurable plasma antenna array (PAA) composed of a metallic half-wavelength dipole and a set of cylindrical plasma discharges arranged in a planar square lattice. Our results, obtained with the linear embedding via Green’s operators (LEGO) method, indicate that beam-forming and beam-steering functionality can be achieved and controlled by appropriately choosing the number and position of the active plasma discharges around the dipole. Furthermore, we show that an external static magnetic field and the plasma density have a noticeable effect on the radiation pattern of the antenna.

A DISPERSIVE CONFORMAL FDTD TECHNIQUE FOR ACCURATE MODELING ELECTROMAGNETIC SCATTERING OF THZ WAVES BY INHOMOGENEOUS PLASMA CYLINDER ARRAY

A dispersive conformal FDTD method has been proposed to accurately model the interface between two adjacent dispersive mediums and implemented to study the scattering of THz electromag- netic (EM) waves by inhomogeneous collisional plasma cylinder array. The method is based on the technology of area average, which is dif- ferent from existing dispersive conformal FDTD schemes. Numerical results show that the proposed method enhances the accuracy level compared to the staircasing FDTD scheme involved in the inhomoge- neous plasma. It is interesting to flnd that the THz EM waves can propagate through the plasma array more easily with higher frequen- cies or larger separations, hence the scattering width in the backward direction becomes smaller, and the forward scattering exhibits a little difierent. This study will be useful for further designing intelligent plasma antenna arrays in the THz band and terahertz reentry teleme- try through plasma.

Radiation Theory of the Plasma Antenna

Several basal theoretical problems for the radiation of plasma antenna are investigated. The system equations are obtained according to the rule of the disturbing current, which is excited by surface waves on the interface between a plasma column and a dielectric tube, and the radiation theory of dielectric antennae. The analysis indicates that there are two kinds of mechanisms to explain the radiation of plasma antennae. The first one is the radiation of the disturbing current, which is similar to the radiation of a metal antenna. In the second case, because the electromagnetic wave partly cannot satisfy the total reflection condition in some specific frequency bands, transmission can be excited in a plasma antenna, which is similar to the radiation of a dielectric antenna. The radiation derived from these two kinds of mechanisms can be superposed in certain frequency bands. In this paper, a radiation directivity function is obtained. The radiation characteristics of plasma antennae are compared with those of metal antennae. The radiation properties of plasma antennae are presented based on numerical calculation. The present results provide an important theory for further investigation in the performance of controlling plasma antennae and plasma antenna arrays.