In order to extend the scanning range of a phased array and maintain the scanning gain flatness, a novel millimeter-wave phased array with four linearly-arranged pattern reconfigurable elements is presented in this communication. The phased array has been designed, fabricated, measured and analyzed. The active patterns of each reconfigurable element are measured at different reconfigurable modes and the pattern scanning performance of the phased array is synthesized by using these active patterns. Furthermore, a genetic algorithm is used to lower the level of side lobes of the proposed phased array. The results show that the phased array can scan its main lobe from -75° to +75° in the elevation plane with a gain fluctuation less than 3 dB.

Research on a Millimeter-Wave Phased Array With Wide-Angle Scanning Performance

This paper presents the research and development of two terahertz imaging systems based on photonic and electronic principles, respectively. As part of this study, a survey of ongoing research in the field of terahertz imaging is provided focusing on security applications. Existing terahertz imaging systems are reviewed in terms of the employed architecture and data processing strategies. Active multichannel measurement method is found to be promising for real-time applications among the various terahertz imaging techniques and is chosen as a basis for the imaging instruments presented in this paper. An active system operation allows for a wide dynamic range, which is important for image quality. The described instruments employ a multichannel high-sensitivity heterodyne architecture and aperture filling techniques, with close to real-time image acquisition time. In the case of the photonic imaging system, mechanical scanning is completely obsolete. We show 2-D images of simulated 3-D image data for both systems. The reconstruction algorithms are suitable for 3-D real-time operation, only limited by mechanical scanning.

Terahertz Imaging Systems With Aperture Synthesis Techniques

In order to improve the wide-angle scanning performance of the phased array antennas, a wide-beam microstrip antenna with metal walls is proposed in this letter. The beamwidth of the antenna is broadened by the horizontal current on the radiating patch and the vertical current on the metal walls. The half-power beamwidth of the E- and H-planes is 221° and 168° at 4.0 GHz. Furthermore, the wide-beam antenna element is employed in a nine-element E-plane linear array antenna. The main beam of the E-plane scanning linear array antenna can scan from −70° to +70° in the frequency band from 3.7 to 4.3 GHz with a gain fluctuation less than 2.7 dB and variation in maximum sidelobe level less than −5.8 dB. The E-plane scanning linear array antenna with nine elements is fabricated and tested. The measured results achieve a good agreement with the simulated results.

A Wide-Angle E-Plane Scanning Linear Array Antenna With Wide Beam Elements

In this paper, an eight-element linear array is proposed and experimentally studied to illustrate the potential of using high impedance surfaces (HISs) for wide-angle scanning applications. An HIS-based horizontal wire antenna with a broad-beam radiation pattern is implemented as the individual radiating elements of the proposed array. The working mechanism of the HIS-based array is investigated as well. The rectangular-mushroom HIS, operating in surface-wave band, contributes to the broad-beam radiation of the individual antenna element as well as the wide scan performance of the array. Measured results show that with uniform magnitude and progressive phase excitation, the array performs a wide scan angle up to 85° in the elevation plane and a realized gain varying from 13.1 to 10.1 dBi. Meanwhile, the side lobe levels (SLLs) are generally less than $-10\;\mathbf{dB}$ over the entire scan region. Good agreement is obtained between the measurements and the simulations.

Investigation of Using High Impedance Surfaces for Wide-Angle Scanning Arrays

Two wide-angle scanning linear array antennas (E- and H-planes scanning linear array antenna) are studied and presented. In order to improve the wide-angle scanning performance of the phased array antenna, a wide beamwidth U-shaped microstrip antenna with the electric walls is designed. The wide-angle scanning linear array antennas are studied in the frequency band from 3.2 to 3.8 GHz. The 3 dB beamwidth of the antenna is 140° in the E-plane scanning linear array center and 220° in the H-plane scanning linear array center at 3.5 GHz. The main beams of the H-plane scanning linear array antenna can scan from −90° to +90° with a gain fluctuation less than 3 dB and a maximum sidelobe level (SLL) less than −5 dB. Simultaneously, the main beam of the E-plane scanning linear array antenna can scan from −75° to +75° with a gain fluctuation less than 3 dB and SLL less than −5 dB. The H- and E-planes scanning linear array antennas with nine elements are fabricated and tested. The measured results have a good agreement with the simulation results.

Study on Wide-Angle Scanning Linear Phased Array Antenna

A compact, wide bandwidth, wide beamwidth resonant microstrip meander line antenna element is reported for active phased array applications. The antenna element offers a return loss better than −10 dB over a bandwidth of 12% in S-band with a beamwidth of 130° in E-plane. The element has been tested in an array for its wide-angle scan performance. Simulated and measured results are presented. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1737–1740, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23531

Resonant microstrip meander line antenna element for wide scan angle active phased array antennas

This paper describes the theory and the experimental results for twist reflector scanning monopulse antenna system at millimeter wave frequencies. A theory has been worked out to predict the performance of the antenna system at boresight and at various scan angles. The theory accounts for the performance variation of the antenna system due to degradation of twist reflector characteristics during scan. The effects due to distortions on transparaboloid and its partial illumination in the scan are also included.

A millimeter wave monopulse twist reflector scanning antenna system : theory and experiment

This paper describes the design of substrate integrated waveguide slot array antenna operating at X-band. Realization of slotted waveguide array with 16 slots has been done using ANSYS HFSS 17. In order to get desired sidelobe levels, non-uniform power distribution with Chebyshev polynomial is used. Substrate Integrated Waveguide technology has been adopted to convert slotted waveguide array antenna into planar form which leads to 50% of the size reduction with comparable performance.

Design of Substrate Integrated Waveguide Slot Array Antenna at X-Band

The paper presents design, simulation and experimental results for the reconfigurable square spiral antenna. This antenna is reconfigurable for two bands: band-I is 0.4–3 GHz which covers G...

Design and Development of Cavity-Backed Reconfigurable Square Spiral Antenna

A unique carrier-recovery technique using a long-loop PLL configuration is suitable for receiving data from multiple satellites with different payload characteristics.

V M Pandharipande

Papers

Resonant microstrip meander line antenna element for wide scan angle active phased array antennas

A millimeter wave monopulse twist reflector scanning antenna system : theory and experiment

Design of Substrate Integrated Waveguide Slot Array Antenna at X-Band

Design and Development of Cavity-Backed Reconfigurable Square Spiral Antenna

Regenerate coherent carriers: From PSK signals