Design and Implementation of High Gain 60 GHz Antennas for Imaging/Detection Systems

Recently, millimeter wave (MMW) imaging detection systems are drawing attention for their relative safety and detection of concealed objects. Such systems use safe non-ionizing radiation and have great potential to be used in several applications such as security scanning and medical screening. Antenna probes, which enhance system performance and increase image resolution contrast, are primarily used in MMW imaging sensors. The unlicensed 60 GHz band is a promising band, due to its wide bandwidth, about 7 GHz (57 - 64 GHz), and lack of cost. However, at 60 GHz the propagation loss is relatively high, creating design challenges for operating this band in MMW screening. A high gain, low profile, affordable, and efficient probe is essential for such applications at 60 GHz. This thesis’s focus is on design and implementation of high gain MMW probes to optimize the performance of detection/imaging systems. First, single-element broadside radiation microstrip antennas and novel probes of endfire tapered slot high efficient antennas are presented. Second, a 57-64 GHz, 1 × 16-element beam steering antenna array with a low-cost piezoelectric transducer controlled phase shifter is presented. Then, a mechanical scanner is designed specifically to test proposed antenna probes utilizing low-power 60 GHz active monostatic transceivers. The results for utilizing proposed 60 GHz probes show success in detecting and identifying concealed weapons and explosives in liquids or plastics. As part of the first research theme, a 60 GHz circular patch-fed high gain dielectric lens antenna is presented, where the prototype’s measured impedance bandwidth reaches 3 GHz and a gain of 20 dB. A low cost, 60 GHz printed Yagi antenna array was designed, optimized, fabricated and tested. New models of the antipodal Fermi tapered slot antenna (AFTSA) with a novel sine corrugated (SC) shape are designed, and their measured results are validated with simulated ones. The AFTSA-SC produces a broadband and high efficiency pattern with the capacity for high directivity for all ISM-band. Another new contribution is a novel dual-polarized design for AFTSA-CS, using a single feed with a pair of linearly polarized antennas aligned orthogonally in a cross-shape. Furthermore, a novel 60 GHz single feed circularly polarized (CP) AFTSA-SC is modeled to radiate in the right-hand circularly polarized antenna (RHCP). A RHCP axial ratio bandwidth of < 3dB is maintained from 59 to 63 GHz. In addition, a high gain, low cost 60 GHz Multi Sin-Corrugations AFTSA loaded with a grooved spherical lens and in the form of three elements to operate as the beam steering antenna is presented. These probes show a return loss reduction and sidelobes and backlobe suppression and are optimized for a 20 dB or higher gain and radiation efficiency of ~90% at 60 GHz. The second research theme is implementing a 1 × 16-element beam steering antenna array with a low-cost piezoelectric transducer (PET) controlled phase shifter. A power divider with a triangular feed which reduces discontinuity from feed lines corners is introduced. A 1 × 16-element array is fabricated using 60 GHz AFTSA-SC antenna elements and showed symmetric E-plane and H-plane radiation patterns. The feed network design is surrounded by electromagnetic band-gap (EBG) structures to reduce surface waves and coupling between feed lines. The design of a circularly polarized 1 × 16-element beam steering phased array with and without EBG structures also investigated. A target detection investigation was carried out utilizing the proposed 60GHz antennas and their detection results are compared to those of V-band standard gain horn (SGH). System setup and signal pre-processing principle are introduced. The multi-corrugated MCAFTSA-SC probe is evaluated with the imaging/detection system for weapons and liquids concealed by clothing, plywood, and plastics. Results show that these items are detectable in clear 2D image resolution. It is believed that the 60 GHz imaging/detection system results using the developed probes show potential of detecting threatening objects through screening of materials and public

High Gain Broadband mm-Wave Antenna Arrays for Short-range Wireless Communication Systems

Recently, the ever-increasing demand for fifth-generation (5G) wireless applications has turned millimeter-wave (mm-wave) multi-beam array antenna into quite a promising research direction. Besides offering a remarkable bandwidth for high-speed wireless connectivity, the short wavelengths (1 to 10 mm) of mm-wave signals makes the size of the antenna array with beamforming network (BFN) compatible with a transceiver front-end. The high losses associated with mm-wave wireless links and systems considered the foremost challenge and may restrict the wireless communication range. Therefore, a wideband substrate integrated waveguide (SIW)-based antenna with high gain and beam scanning capabilities would be a solution for these challenges, as it can increase the coverage area of mm-wave wireless systems and mitigate the multipath interference to achieve a high signal to noise (S/N) ratio, and thereby fulfill the link budget requirements. This thesis focuses on the analysis and design of single- and multi-beam mm-wave antenna arrays based on SIW technology to fulfill the growing demand for wideband high-gain planar antenna arrays with beam steering capability at V-band. A tapered slot antenna (TSA) and cavity-backed patch antenna are used as the main radiators in these systems to achieve high-gain and high efficiency over a wide range of operating frequencies. Accordingly, numerous design challenges and BFN-related issues have been addressed in this work. Firstly, an antipodal Fermi tapered slot antenna (AFTSA) with sine-shaped corrugations is proposed at V-band. The antenna provides a flat measured gain of 20 dB with a return loss better than 22 dB. In addition, A broadband double-layer SIW-to-slotline transition is proposed to feed a planar linearly tapered slot antenna (PLTSA) covering the band 46-72 GHz. This new feeding technique, which addresses the bandwidth limits of regular microstrip-to-slotline transitions and avoids the bond wires and air bridges, is utilized to feed a 1x4 SIW-based PLTSA array. Secondly, a new cavity-backed aperture-coupled patch antenna with overlapped 1-dB gain and impedance bandwidth of 43.4 % (56-87 GHz) for |S11| < -10 dB and an average gain of 8.2 dBi is designed. A detailed operating principle is presented. Based on the proposed element, an SIW based 1x8 array is constructed, whose beam-shape is synthesized by amplitude tapering according to Taylor distribution to reduce the sidelobe level. Moreover, a four-layered 4x4 cavity-backed antenna array with a low-loss full-corporate SIW feed network is implemented for gain and aperture efficiency enhancement. The measured results exhibited a bandwidth of 38.4 % (55.2-81.4 GHz) for |S11| < -10 dB and a gain of 20.5 dBi. A single-layer right-angle transition between SIW and air-filled WR15 waveguide along with an equivalent circuit model is introduced and used to measure the performance of both proposed linear and planar arrays. Thirdly, two 1-D scanning multi-beam array designs based on SIW technology, at 60 GHz, have been presented. The first design is a compact multi-beam scanning 4x4 slot antenna array with broadside radiation. The BFN is implemented using a dual-layer 4x4 Butler matrix, where the 450 and 00 phase shifters are designed on a separate layer with different permittivity, resulting in a significant size reduction compared to a conventional single layer. A detailed theoretical analysis, principle of operation and the circuit-model of the proposed phase shifter have been discussed, showing less desperation characteristics compared to ordinary phase shifters. The measured results show an azimuthal coverage of 1210. The second design is a wideband high gain multi-beam tapered slot antenna array with end-fire radiation. An SIW Butler matrix with a modified hybrid crossover is used as a BFN. The fabricated prototype exhibits a field of view of 970 in the azimuthal plane, with measured gain ranges from 12.7 to 15.6 dBi. Lastly, a novel three-layered SIW-fed cavity-backed linearly polarized (LP) patch antenna element is presented, covering a bandwidth of 36.2 % (53-76.4 GHz) with a flat gain ranging from 7.6 to 8.2 dBi. A compact two-layered beam forming network is designed with a size reduction of 28 % compared to a standard one-layered BFN without affecting its s-parameters. The results show that the impedance bandwidth is 31.1 % (51.5-70.5 GHz) for |S11|<-16 dB with an average insertion loss of 1.3 dB. The proposed antenna element and BFN are employed to form a compact 2x2 multibeam array at 60 GHz for 2-D scanning applications. The array shows a bandwidth better than 27 % with a radiation gain of up to 12.4 dBi and radiation efficiency of 80%. The multi-beam array features four tilted beams at 330 from a boresight direction with 450, 1350, 2250 and 3150 in azimuth directions, i.e., on e beam in each quadrant

NASA patent abstracts bibliography: A continuing bibliography. Section 1: Abstracts (supplement 39)

Abstracts are provided for 154 patents and patent applications entered into the NASA scientific and technical information systems during the period Jan. 1991 through Jun. 1991. Each entry consists of a citation, an abstract, and in most cases, a key illustration selected from the patent or patent application

Integral Optics: Lecture Notes

An introduction is given to the principles of integrated optics and optical guided-wave devices. The characteristics of dielectric waveguides are summarized and methods for their fabrication are described. An illustration is given of recent work on devices including directional couplers, filters, modulators, light deflectors, and lasers. The textbook reflects the latest achievements in the field of integrated optics, which have had a significant impact on the development of communication technology and methods for transmitting and processing information

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion

Metamaterial

In-depth analysis of the theory, properties and description of the most potential technological applications of metamaterials for the realization of novel devices such as subwavelength lenses, invisibility cloaks, dipole and reflector antennas, high frequency telecommunications, new designs of bandpass filters, absorbers and concentrators of EM waves etc. In order to create a new devices it is necessary to know the main electrodynamical characteristics of metamaterial structures on the basis of which the device is supposed to be created. The electromagnetic wave scattering surfaces built with metamaterials are primarily based on the ability of metamaterials to control the surrounded electromagnetic fields by varying their permeability and permittivity characteristics. The book covers some solutions for microwave wavelength scales as well as exploitation of nanoscale EM wavelength such as visible specter using recent advances of nanotechnology, for instance in the field of nanowires, nanopolymers, carbon nanotubes and graphene. Metamaterial is suitable for scholars from extremely large scientific domain and therefore given to engineers, scientists, graduates and other interested professionals from photonics to nanoscience and from material science to antenna engineering as a comprehensive reference on this artificial materials of tomorrow

NASA patent abstracts bibliography: A continuing bibliography. Section 1: Abstracts (supplement 44)

Abstracts are provided for 131 patents and patent applications entered into the NASA scientific and technical information system during the period Jun. 1993 through Dec. 1993. Each entry consists of a citation, an abstract, and in most cases, a key illustration selected from the patent or patent application

NASA patent abstracts bibliography: A continuing bibliography. Section 2: Indexes (supplement 36)

A subject index is provided for over 4600 patents and patent applications for the period May 1969 through December 1989. Additional indexes list personal authors, corporate authors, contract numbers, NASA case numbers, U.S. patent class numbers, U.S. patent numbers, and NASA accession numbers