Antipodal curvedly tapered slot antennas (ACTSAs) with different slot profiles are investigated to achieve the optimum circular polarization performance. The profiles of the tapered slots can be determined by different curves, such as linear, exponential, and logarithmic curves. Therefore, the corresponding waveguide-fed circularly polarized (CP) antipodal linear, exponential, exponential-logarithmic tapered slot antennas (AL-, E-, EL-TSA) are designed, fabricated, and measured at Ka-band for a comprehensive study. The optimized AELTSA provides good impedance matching, gain above 10.3 dBi, sidelobe lower than $-15 {\rm dB}$ , low cross-polarization, and left-hand circularly polarized (LHCP) axial ratio (AR) lower than 3 dB, from 28 to 40 GHz. Moreover, a waveguide-fed LHCP antipodal exponential–exponential tapered slot antenna (AEETSA) is designed at 500 GHz and fabricated by silicon micromachining. The radiation characteristics are examined by measurement results of symmetric beams and ARs lower than 1.5 dB, from 490 to 510 GHz.

Millimeterwave and Terahertz Waveguide-Fed Circularly Polarized Antipodal Curvedly Tapered Slot Antennas

The design and optimization of very broadband integrated lens antennas (ILAs) constitutes one of the future trends in lens antenna field. To this end we investigate numerically the radiation performance of millimeter wave ILAs coated with multiple anti reflection layers. We propose lens structures of moderate size (four wavelengths in diameter at the center frequency) and made from a dense dielectric material (ceramic). They are illuminated by two kinds of on-axis primary sources, namely a dielectric-loaded metallic waveguide and a patch antenna. This enables to assess the role of the lens illumination law on the performance of broadband ILAs. In particular, we demonstrate that ILAs coated with three stacked quarter wavelength matching layers exhibit a very broadband promising features. First their radiation characteristics remain very stable over a large frequency band: a 36% relative bandwidth is achieved using dielectric-loaded waveguide feeds. Secondly very high values of aperture efficiencies (beyond 91% over a 21% bandwidth) are obtained using printed feeds. The truncation effects of the ground plane and substrate of planar feeds upon the beam characteristics are also studied. We conclude that they must be taken into account at the very first stages of the design process of ILAs.

Very Broadband Extended Hemispherical Lenses: Role of Matching Layers for Bandwidth Enlargement

IEEE microwave and guided wave letters : a publication of the IEEE Microwave Theory and Techniques Society

This paper presents a low-profile, high-performance, and low-cost Ka -band circularly polarized (CP) passive phased-array antenna (PAA) system. A $1\times 4$ passive subarray operating at the Ka -band frequency band is investigated, developed, and tested as a possible building block for mobile satellite communication systems. In particular, a CP antenna integrated with a high-performance passive phase shifter is presented and experimentally verified. A new low-cost and low-profile magnetic actuator is proposed to precisely control the phase state of the phase shifter. A 3-D printed polymer package is utilized to enclose the phase shifter and reduce the environmental effects. The proposed CP passive PAA achieves high-performance right-hand CP radiation with high cross-polarization discrimination over a wide scan angle from 0° to ±38° over the frequency band (29.5–30.5 GHz). An axial ratio (AR) < 3 dB is demonstrated over the entire scanning range. Moreover, the measured radiation efficiency is 60% at boresight. The gain drops by 1 dB at ±38° scanning angles.

A Low-Cost Ka -Band Circularly Polarized Passive Phased-Array Antenna for Mobile Satellite Applications

We investigate the radiation capabilities of focal array fed dielectric lens antennas using the FDTD method. Several relevant configurations sharing the same lens architecture (namely an extended hemispherical lens coated with a quarter wavelength matching layer), but illuminated by different sub-array topologies, are compared. In particular, we study the impact of the feeding amplitude coefficients, sub-array size and location upon the radiation patterns and beam scanning performance of the lens. Our numerical results demonstrate that such lens configurations are very attractive and flexible for beam synthesis at millimeter waves (beam shaping, beam scanning and beam reconfiguration). These conclusions are confirmed successfully by several experimental results in Ka-band obtained with a 8 × λ0 lens in Rexolite illuminated by linear printed antenna arrays of variable size.

Focal Array Fed Dielectric Lenses: An Attractive Solution for Beam Reconfiguration at Millimeter Waves

Millimeter wave technology advances have made possible active and passive millimeter wave imaging for av ariety of applications including advanced plasma diagnostics, radio astronomy, atmospheric radiometry, concealed weapon detection, all-weather aircraft landing, contraband goods detection, harbor navigation/surveillance in fog, highway traffi cm onitoring in fog, helicopter and automotive collision avoidance in fog, and environmental remote sensing data associated with weather, pollution, soil moisture, oil spill detection, and monitoring of forest fires, to name but a few. The primary focus of this paper is on technology advances which have made possible advanced imaging and visualization of magnetohydrodynamic (MHD) fluctuations and microturbulence in fusion plasmas. Topics of particular emphasis include frequency selective surfaces, planar Schottky diode mixer arrays, electronically controlled beam shaping/steering arrays, and high power millimeter wave local oscillator and probe sources. c

http://www.jspf.or.jp/PFR/PDF/pfr2007_02-S1019.pdf

Advanced Microwave/Millimeter-Wave Imaging Technology

An investigation of the receiving properties of both 1D 13-element and 2D 8 × 4-element dual dipole antenna arrays on an elliptical MACOR lens from Q- to V-band is reported. Theoretical and measurement results agree well. The intended application is for millimeter wave plasma radar reflectometric imaging, although the results have broader applicability (Munsat et al., Rev Sci Instrum 74 (2003) 1426–1432). © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1798–1801, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22620

Q‐band to V‐band 1D and 2D elliptical lens antenna arrays

In this paper, the design and testing of an 8-element E-plane array of antipodal elliptically-tapered slot antennas designed in Ka-band is described. A low-cost E-plane beam scanning and beam broadening capability is realized using a true time delay piezoelectric transducer (PET)-controlled phase shifter. The beam is steered from -21deg to +24deg and the 3 dB beamwidth is widened by about 10deg, the latter being the requirement for the plasma radar reflectometric imaging application

Ka-Band True Time Delay E-plane Beam Scanning and Broadening Phased Array System using Antipodal Elliptically-Tapered Slot Antennas

In this letter, we present a Ka-band 8-element E-plane beam steering/shaping phased antenna array (PAA) using antipodal elliptically tapered slot antenna (AETSA). The power feeding network, phase shifter and antenna element were fabricated on a single low cost PCB substrate to avoid the extra loss caused by connection of different circuit pieces and for easier integration and easier fabrication. The system achieved wide scanning angle, which is from −21° to +24° and the 3 dB beamwidth is widened by 10°, the latter being the requirement for plasma imaging application.

Ka-band E-plane Beam Steering/Shaping Phased Array System Using Antipodal Elliptically-tapered Slot Antenna

This paper presents the design and measurement of a 20 to 40 GHz beam shaping/steering Fermi-type tapered slot antenna array. The arrays are fabricated using the electro fine forming (EF2) fabrication technology*. The progressive phase shift is realized by a piezoelectric transducer (PET) controlled phase shifter on coplanar stripline (CPS). Compared to the perturbation on a microstrip line, the CPS provides 50% more phase shift. A Taylor N-Bar distribution is introduced to lower the sidelobe ratio (SLR) in beam shaping, which is necessary for many applications including modern microwave telecommunication systems.

Lu Yang

Papers

Advanced Microwave/Millimeter-Wave Imaging Technology

Q‐band to V‐band 1D and 2D elliptical lens antenna arrays

Ka-Band True Time Delay E-plane Beam Scanning and Broadening Phased Array System using Antipodal Elliptically-Tapered Slot Antennas

Ka-band E-plane Beam Steering/Shaping Phased Array System Using Antipodal Elliptically-tapered Slot Antenna

20 to 40 GHz Beam Shaping/Steering Phased Antenna Array System using Fermi Tapered Slot Antennas