Vladimir A. Manasson

MMW scanning antenna

Cost reduction is one of the most important considerations in millimeter-wave (MMW) radar development. Hardware, especially the phase-shifters, for electronic beam scanning in the MMW band presents very complex fabrication challenges that dramatically raise the device cost. A typical mechanically-scanning antenna contains one or more hinged parts (lenses, mirrors or feeds). In operation they experience strong mechanical accelerations, and other forces that sharply limit the scanning speed. We propose a solution to this problem, using a leaky-wave periodically loaded antenna design and a new architecture. This paper presents the basic design, and discusses related issues.

Millimeter‐wave optically scanning antenna based on photoinduced plasma grating

The photocontrolled millimeter-wave (MMW) antenna is an alternative approach to the phased array. It offers a high potential to decrease fabrication cost. We describe a new MMW scanning antenna controlled by light. The basic antenna element is a semiconductor plate containing a photoinduced plasma grating (PIPG). By changing the grating period and rotating the grating, the device is able to scan a MMW beam in two dimensions. To enhance antenna efficiency, we use an antenna design that takes advantage of the reflectance of the MMW mirror behind the semiconductor plate. We found that the pulse duration of the pumping light can strongly affect the antenna’s output. Our calculations demonstrate that diffusion is responsible for decay of antenna efficiency.

Helicopter obstacle detection radar system

We have analyzed and experimentally tested the feasibility of thin wire detection using millimeter wave radar. The radar system includes a novel, fast scanning antenna and a transceiver/signal processor unit from BAE systems.

Real-time visualization using a 2D/3D imaging MMWave radar

This paper describes a novel approach to the real-time visualization of 3D imagery obtained from a 3D millimeter wave radar. The radar system uses two scanning beams to provide all weather 3D distance measurements of objects appearing on the ground. This information is displayed using our high-end 3D visualization engine capable of delivering models of up to 100,000 polygons with 30 frames per second. The resulting 3D models can then be viewed from any angle and subsequently processed to integrate match them against 3D model data stored in a synthetic database. The resulting Synthetic Radar Vision System will provide a truly novel way to obtained all weather 3D images. The paper will focus on the real-time imaging and display aspects of our solution, and will discuss technical details of the radar design itself. Engineering challenges will be outlined in the context of a practical application.

GaN : based terahertz sources

We discuss possible new sub-millimeter sources based on group-III Nitrides superlattices. It is shown that traveling dipole domains in biased GaN/InGaN and GaN/AlGaN short- period superlattices can generate electromagnetic power in the terahertz region.

Novel passive millimeter-wave imaging system: prototype fabrication and testing

A novel passive millimeter wave imaging (PMMW) system that utilizes a special arrangement of N equals 36 focal plane elements is presented. N MMW radiometric receivers generate a N X N PMMW image. We discuss the system fabrication and testing.

MMW optically scanning antenna based on plasma-induced grating

A light-induced grating aperture (LIGA) is a semiconductor plate containing a periodic structure formed of nonequilibrium light-induced electron-hole plasma. The presence of excess charge carriers in a semiconductor medium locally changes the dielectric constant of the material. Such a light-induced periodic structure can serve as a diffraction grating for millimeter waves (MMW), and generates diffracted beams propagating in directions distinct from that of the incident beam. The angle between the incident and diffracted beams depends on the period (Lambda) of the light-induced grating, a parameter that can be controlled using a liquid crystal display (LCD). The effect is strong enough not only for academic study but for practical application as well. The authors fabricated a new scanning MMW antenna in which MMW is diffracted by a LIGA.

Laser warning receiver based on coherence discrimination

A new design of a laser warning receiver is proposed. We use temporal coherence as a specific attribute of laser radiation distinguishing it from background noise and from other non coherent radiation. In this paper we describe coherent discriminators, operating in a wide range of frequencies, which can discriminate both pulsed and CW laser radiation in a wide spectral band. Preliminary tests have demonstrated the devices operation.

Conductive coating with infrared pass band

Transparent conductors find applications in electrodes for flat panel displays, electromagnetic shielding, optical filters, antennas embedded in windshields, transparent electrodes for light-emitting diodes and lasers. Shields transparent in the atmospheric spectral windows of (3- 5)μm or (10-12)μm are in demand for electromagnetic protection of infrared displays in thermo-imaging devices. We propose semiconductor/dielectric or metal/dielectric multilayers that can serve as shield against RF and microwave radiation, while being transparent in the mid-infrared spectral region.

Beam-steering control in plasma-grating antennas

Continuous beam steering can be achieved in plasma-grating antennas that employ an array of optical fibers or electrodes set at fixed positions. Effects of both continuous and discrete-level illumination are considered.