Millimeter-wave Planar Research Articles

Uncertainties Introduced by the Probe in Millimeter-Wave Planar Near-Field Measurements

Uncertainties Introduced by the Probe in Millimeter-Wave Planar Near-Field Measurements

Ultra-Wideband Millimeter-Wave Planar Array Antenna With an Upside-Down Structure of Printed Ridge Gap Waveguide for Stable Performance and High Antenna Efficiency

In this letter, a wideband millimeter-wave (mmWave) planar array antenna with a printed ridge gap waveguide (PRGW) feeding network is presented. A planar bowtie antenna fed by the PRGW is employed as the array radiation element which combines the bowtie with an upside-down electromagnetic bandgap part by using lamination. Thus, with this new upside-down structure, the proposed array antenna achieves a stable, wideband, and high-antenna-efficiency performance. A prototype of 8 ×8 array is fabricated and measured. The measured results show that the proposed array has an impedance matching bandwidth (|S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> | <; -10 dB) of 50.3% from 18.6 to 31.1 GHz. The maximum measured gain is 22.1 dBi at 29 GHz, and the total antenna efficiency is above 60% with a bandwidth of 45% from 18.8 to 29.8 GHz.

A Planar Millimeter-Wave Resonator-Array to Sense the Permittivity of COP Film with the 5G Handset Back-Cover.

In this paper, a new sensor is developed to estimate the dielectric constant of Cyclo Olefin Polymer (COP) film utilizable for 5G mobile phones’ multi-layered back-cover. It is featured by the electrical characterization of the thin layer of the COP film at 28 GHz as the material under test (MUT) directly contacting the planar probe (which is an array of resonating patches) and a new meta-surface as metal patterned on the COP film inserted between the planar probe and the 5G multi-layered back-cover for enhanced physical interpretation of the data by way of impedance matching. In this approach to delving into the material, a thin and small meta-surface film with an area of 25.65 × 21.06 mm2 and a thickness of 55 μm is examined for applications to 5G mobile 28 GHz-frequency communication on the basis of the below −10 dB-impedance matching for the 1-by-4 array sensor. Along with this, the real and commercial handset back-cover is brought to the test. The proposed method presents the advantages of geometrical adequacy to the realistic 5G handset antenna configuration, the idea of impedance-matching via meta-materials, and the suitability of characterizing the film-type structure as compared to the open-ended coaxial waveguide, waveguide-to-waveguide and TX horn-to-RX horn free-space test methods.

Noncontact Group-Delay-Based Sensor for Metal Deformation and Crack Detection

A millimeter-wave planar resonator sensor for the detection of deformation and crack in metal device with high precision and sensitivity is presented in this article. The deformation and crack directly imply great damage in the industrial metal structures, which made the detection crucial in structural health monitoring. The main structure of the proposed sensor is based on the concept of multiband electromagnetic induced transparency (EIT) effect. EIT effect is an interference quantum phenomenon, which can be realized in microwave band by electromagnetic resonate structures. Multiband EIT is actualized using a series of split-ring resonators (SRR) coupling with each other to produce one wide stopband and four narrow passbands. The resonance frequencies of the SRRs are affected by the variation of coupling amount between the SRRs and the part of metal device under test that places close to the specific SRR. The orientation of metal deformation and crack is achieved by different frequency shifts of the four independent group delay peaks induced by multiband EIT. Thus, the proposed sensor can orientate the deformation on the metal device with the precision of 1.3 MHz/μm.

Near-Field Three-Dimensional Planar Millimeter-Wave Holographic Imaging by Using Frequency Scaling Algorithm

In this paper, a fast three-dimensional (3-D) frequency scaling algorithm (FSA) with large depth of focus is presented for near-field planar millimeter-wave (MMW) holographic imaging. Considering the cross-range range coupling term which is neglected in the conventional range migration algorithm (RMA), we propose an algorithm performing the range cell migration correction for de-chirped signals without interpolation by using a 3-D frequency scaling operation. First, to deal with the cross-range range coupling term, a 3-D frequency scaling operator is derived to eliminate the space variation of range cell migration. Then, a range migration correction factor is performed to compensate for the residual range cell migration. Finally, the imaging results are obtained by matched filtering in the cross-range direction. Compared with the conventional RMA, the proposed algorithm is comparable in accuracy but more efficient by using only chirp multiplications and fast Fourier transforms (FFTs). The algorithm has been tested with satisfying results by both simulation and experiment.

Near-Field Three-Dimensional Planar Millimeter-Wave Holographic Imaging by Using Frequency Scaling Algorithm

In this paper, a fast three-dimensional (3-D) frequency scaling algorithm (FSA) with large depth of focus is presented for near-field planar millimeter-wave (MMW) holographic imaging. Considering the cross-range range coupling term which is neglected in the conventional range migration algorithm (RMA), we propose an algorithm performing the range cell migration correction for de-chirped signals without interpolation by using a 3-D frequency scaling operation. First, to deal with the cross-range range coupling term, a 3-D frequency scaling operator is derived to eliminate the space variation of range cell migration. Then, a range migration correction factor is performed to compensate for the residual range cell migration. Finally, the imaging results are obtained by matched filtering in the cross-range direction. Compared with the conventional RMA, the proposed algorithm is comparable in accuracy but more efficient by using only chirp multiplications and fast Fourier transforms (FFTs). The algorithm has been tested with satisfying results by both simulation and experiment.

Development of Millimeter-Wave Planar Antennas Using Low-Loss Materials

As the importance of advanced millimeter-wave diagnostics increases, the fabrication of high-performance devices and components becomes essential. In this paper, we describe the development of millimeter-wave planar antennas using low-loss fluorine substrates. The problems to be solved in this study are the low degree of adhesion between copper foil and the fluorine substrate and the accuracy of device pattern using conventional fabrication techniques. In order to solve these problems, a new surface treatment of fluorine films and a fabrication method using electro-fine-forming (EF2) are proposed. In order to confirm the performance of the treated films, microstrip lines (MSLs) and planar patch antennas with a low sidelobe level in the E-plane are designed and fabricated on conventional fluorine substrates and grafted poly(tetrafluoroethylene) (PTFE) films.

Planar $Ku$-Band 4$\,\times\,$4 Nolen Matrix in SIW Technology

In this paper, a 4 × 4 Nolen matrix beam-forming network for multibeam antenna applications is designed and demonstrated at 12.5-GHz center frequency. The structure is implemented using substrate integrated waveguide (SIW) technology for its attractive advantages including compact size, low loss, light weight, and planar form well suitable for high-density integration with other microwave and millimeter-wave planar integrated circuits. SIW cruciform couplers are used as fundamental building blocks for their wide range of coupling factors and their specific topology well adapted to the serial feeding topology of a Nolen matrix. The network performances are investigated over a 500-MHz frequency bandwidth ranging from 12.25 to 12.75 GHz. The matrix definition based on SIW cruciform couplers is similar to its microstrip counterpart in terms of coupling factors and phase delays. The whole network is fabricated. Measured results are in good agreement with the theoretical predictions, thus validating the proposed design concept. Using this matrix with a four radiating elements array antenna enables us to investigate the impact of the proposed matrix on the beam pointing angles versus frequency.

Benzocyclobutene as Substrate Material for Planar Millimeter-Wave Structures: Dielectric Characterization and Application

The application of benzocyclobutene (BCB) polymer as dielectric substrate material for millimeter-wave microstrip structures is investigated in this paper to face the problem of large losses due to standard dielectrics in the high microwave range. Dielectric properties of BCB are characterized from S-parameter measurements on a conductor-backed coplanar waveguide (CBCPW) using the polymer as substrate material. Excellent features, with a low loss tangent and a stable dielectric constant, are demonstrated within the measurement range from 11 GHz to 65 GHz. As a validation of BCB high frequency performances, the design and experimental characterization of a V-band array on BCB substrate is presented. Measurement results on both matching and radiation characteristics of the millimeter-wave array are discussed.

New Advanced Fabrication Technique for Millimeter-Wave Planar Components based on Fluororesin Substrates using Graft Polymerization

As the importance of advanced millimeter-wave diagnostics increases, a reliable and accurate fabrication technique for high-performance devices and relevant components is essential. We describe a new improved fabrication technique for millimeter-wave planar components, such as antennas using low-loss fluororesin substrates. A fragile adhesion between the copper foil and fluororesin substrate and the accuracy of the device pattern using conventional fabrication techniques have been prime suspects in the failure of the devices. In order to solve these problems, surface treatment of fluororesin films and a fabrication method using electro-fine-forming (EF2) are proposed. The peel adhesion strength between the metal and fluororesin films and the value of the dielectric constant of the fluororesin films before and after grafting are reported. A prototype antenna using conventional fluororesin substrates and grafted-poly(tetrafluoroethylene) (PTFE) films produced using the EF2 fabrication technique are also introduced.

Super-Compact Substrate Integrated Waveguide Cruciform Directional Coupler

A super-compact substrate integrated waveguide (SIW) directional coupler is proposed and demonstrated. This coupler consists of a simple cross-over of two SIW sections with two inductive metallic posts in a square junction, showing a cruciform. Attractive features including compact size and planar form make this coupler structure easily integrable in microwave and millimeter-wave planar circuits, especially in beam-forming networks. A 3-dB coupler operating at 24GHz is designed using HFSS, fabricated and measured. Characteristics of 15dB isolation and 90deg phase shift between the output and coupled ports are achieved over 18% bandwidth. Design considerations and simulated as well as measured results are presented and discussed.

Development of Millimeter-Wave Planar Diplexers Based on Complementary Characters of Dual-Mode Substrate Integrated Waveguide Filters With Circular and Elliptic Cavities

A novel high-performance millimeter-wave planar diplexer is developed based on the complementary characters of substrate integrated waveguide (SIW) dual-mode filters with circular and elliptic cavities by making the tradeoff between the isolation, insertion loss, and selectivity. The responses of the dual-mode SIW circular and elliptic cavities are first investigated. It can be found that the upper side response of the circular cavity and the lower side response of the elliptic cavity are very steep. The diplexers with high isolation performance are then designed based on the complementary response characters of circular and elliptic cavities. A diplexer with two dual-mode SIW circular and elliptic cavities is designed and fabricated with a normal printed circuit board process. The measured insertion losses are 1.95 and 2.09 dB in the upper and lower passbands centered at 26 and 25 GHz with the fractional bandwidths of 5.2% and 5.4%. The isolation is lower than - 50dB

Advanced Fabrication Method of Planar Components for Plasma Diagnostics

Kyushu Hitachi Maxell, Ltd, Tagawa-gun, Fukuoka 822-1296, Japan(Received 4 December 2006 /Accepted 11 March 2007)As the importance of plasma imaging diagnostics increases, the fabrication of high performance millimeter-wave planar components becomes essential. This paper describes the development of high performancemillimeter-wave planar components such as antennas and filters using a low-loss fluorine substrate. The prob-lems to be solved are the low degree of adhesion between copper foil and the fluorine substrate and the shape ofthe antenna pattern. In order to solvetheproblems, surface treatment of fluorine films and a fabrication methodusing Electro Fine Forming (EF2) are utilized.

Domain decomposition FDTD algorithm combined with numerical TL calibration technique and its application in parameter extraction of substrate integrated circuits

An efficient hybrid algorithm, known as the decomposition finite-difference time-domain (DD-FDTD) method combined with a numerical thru-line (TL) calibration technique, is proposed and developed for the accurate parameter extraction of microwave circuits and structures. By means of a TL technique, the developed FDTD algorithm not only greatly increases the accuracy of numerical simulations but it also saves computation time and memory space. Moreover, the hybrid algorithm can be used for the parameter extraction of arbitrary complex circuits and structures, such as substrate integrated circuits (SICs). The SICs that are studied in this work are based on substrate integrated waveguides, which are useful for the design of millimeter-wave planar circuits such as filters, resonators, and antennas. On the basis of the characteristic features of numerical calibration process, an idea of domain decomposition is introduced to simplify the procedure of programming and simulation and to increase the simulation's reliability. Simulation and measurement results have verified this hybrid algorithm

Characteristics of Radio Telescopes with Multielement Microstrip Focal Arrays

We calculate beam patterns (BPs) and power characteristics of radio telescopes in the multibeam regime with the use of different types of microstrip focal arrays. A “terrace” design of focal array for illumination of the asymmetric secondary mirror of the RATAN-600 radio telescope and a symmetric paraboloid dish is proposed. Ways for optimization of this type of array are considered. Characteristics of a radio telescope with a millimeter-wave planar circularly polarized focal array are calculated. Some applications of multibeam microstrip focal arrays are considered.

A broadband beam‐fixed planar‐array antenna using slot pair and conductive bar at millimeter‐wave frequencies

AbstractThis paper presents a broadband millimeter‐wave planar‐array antenna that uses a slot pair and crossing conductive bar. The antenna is fed by a waveguide feed network in the E‐plane to reduce the feed‐line loss and a microstrip‐feed network in the H‐plane in order to decrease fabrication costs. The waveguide and microstrip are coupled through the slot pair, which is placed a quarter guided‐wavelength distance apart, so that the reflected waves from the slots cancel each other. As a result, the antenna exhibits very broadband characteristics. The conductive bar is laid above the slots to increase the coupling. Results from simulation and measurement of the fabricated antenna show the reflection bandwidth to be more than 7.1% of the 40.5–43.5‐GHz frequency range. The antenna also has fixed beams, low side‐lobe levels (SLLs) at all frequencies of interest, and a high gain of 28.1 dBi at 41.5 GHz. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 150–154, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20076

Organic micromachining techniques for mass production of millimeter-wave and submillimeter-wave planar circuits

In this paper we present a range of organic micromachining techniques that enable a planar membrane-based printed circuit to be fabricated on a 5 μm thick organic membrane in the absence of any steps involving thermal oxidation and low pressure chemical vapor deposition. The technologies are suitable for mass production of millimeter-wave or submillimeter-wave components. Transmission losses of a membrane-supported E-plane component are typically less than 0.5 dB/cm.

A plate Luneberg lens with the permittivity distribution controlled by hole density

AbstractThe Luneberg lens enables easy beam scanning and has the possibility of multibeam forming. In order to apply these characteristics to a planar antenna, it is first necessary to discuss a method of fabrication for a thin‐plate Luneberg lens. On the other hand, there is a method of controlling permittivity whereby many holes having diameters sufficiently smaller than the wavelength are created in the dielectric material. Permittivity control by the hole density has been used as a method of adjusting the permittivity over a wide range in order to realize a matching layer for the lens, by creating many holes in the direction perpendicular to the incident electric field or close to this direction. In contrast, the authors propose a method for adjusting the permittivity over a wide range by creating multiple holes parallel to the electric field. By means of the hole density method, a Luneberg lens is fabricated. The operating characteristics are determined at 10 and 48 GHz. It is confirmed that the structure works well as a Luneberg lens at both frequencies. Further, as an example of the applications of the plate Luneberg lens, a parallel plate slot array antenna is fabricated and its radiation characteristics are measured. It is found that the Luneberg lens can be applied as the feed section of a high‐gain millimeter‐wave planar antenna with a beam scanning capability. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(9): 1–12, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1120

Analysis Methods for RF, Microwave, and Millimeter-Wave Planar Transmission Line Structures

This book covers the analysis methods of planar transmission line structures from basics to advanced levels. All important fundamental concepts and principles are covered as far as is possible within a text of reasonable size. The content of the book may be split into three parts. The introduction gives a perspective of realized applications that require a thorough mathematical treatment. In the second part the essential fundamentals of electromagnetic theory are explained. A reader with some basic knowledge of vector mathematics can easily follow the treatment of Maxwell's equations in the text. The author not only explains the rules, but also gives valuable hints on how to solve special problems, thus reducing the otherwise inevitable search of the literature. In the third part various methods used to solve Maxwell's equations are described and applied to many to the usual realized line systems. A mathematical treatment as well as practical formulas and results of commonly used structures are provided. The examples guide the reader from the start to the solution of the problem (e.g. Schwarz-Christoffel Mapping). This book, with its thorough mathematical treatment, addresses students of electromagnetic theory but it also addresses the engineer who is in need of knowledge and practical, easy-to-apply formulas for the various line systems. It would have been better if a discussion of important and emerging numerical methods such as FDFD and FDTD had been included. F J Schm�ckle

Scaling-function based multiresolution time domain analysis for planar printed millimetre-wave integrated circuits

The paper applies a scaling-function based multiresolution time domain (MRTD) scheme, in conjunction with an anisotropic perfectly matched layer (APML) for open and PEC-shielded boundary truncations, to analyse various planar millimetre-wave integrated circuits (MICs). Although adding complexity in deriving update equations and extracting MIC characteristics compared with the conventional finite difference time domain (FDTD) method, the MRTD scheme does provide a systematic, constructive, and flexible tool for the analysis of practical planar printed MIC structures. In particular, it is shown that the MRTD scheme is very efficient and requires only about 15% of the computational space and 25% or less of the time needed for the conventional FDTD techniques for all structures investigated in this research.