A5101825678- Microwave and Dielectric Measurement Techniques
- Microwave Engineering and Waveguides
- Acoustic Wave Resonator Technologies
- Magnetic Properties and Synthesis of Ferrites
- Electromagnetic wave absorption materials
- Photonic and Optical Devices
- Spectroscopy and Laser Applications
- Advanced Antenna and Metasurface Technologies
- Microwave Dielectric Ceramics Synthesis
- Magneto-Optical Properties and Applications
- Terahertz technology and applications
- Spectroscopy and Quantum Chemical Studies
- Advanced Fiber Optic Sensors
- Gyrotron and Vacuum Electronics Research
- Antenna Design and Analysis
- Microwave Imaging and Scattering Analysis
- Photonic Crystals and Applications
- Semiconductor Quantum Structures and Devices
- Semiconductor materials and interfaces
- Optical and Acousto-Optic Technologies
- Analytical Chemistry and Sensors
- Electromagnetic Compatibility and Measurements
- Ultrasonics and Acoustic Wave Propagation
- Mechanical and Optical Resonators
- Optical Polarization and Ellipsometry
Tufts University
2012-2022
Massachusetts Institute of Technology
1980-2005
City College of New York
1985-2005
City University of New York
1985-1986
City College
1985-1986
The Graduate Center, CUNY
1985-1986
National Physical Laboratory
1974-1981
Birkbeck, University of London
1973-1977
Rijksmuseum
1977
University of London
1976
This review covers approximately 15 years of development in the techniques used to measure dielectric properties materials over frequency range 1 MHz 1500 GHz. An introductory section summarizes broad trends and is followed by short sections which deal with developments at a more detailed level. The approaches described include time- frequency-domain methods; reflection, transmission, resonant methods, guided free-space discrete-frequency broad-band especially Fourier Transform Spectroscopy....
Various advances in technique have enabled new measurements to be made over a greatly extended frequency range (6<ν∼<450cm−1) of the optical constants n(ν∼) and α(ν∼) liquid water D2O at 19°C. The origin polarization this region is discussed.
It is no longer necessary to use extrapolated microwave dielectric data when designing millimeter-wave components, devices, and systems. Precision measurements can now be made generate highly accurate (5 1/2 mm) continuous spectra on complex refractive index, permittivity, loss tangent for a variety of materials such as common ceramics, semiconductors, crystalline, glassy materials. The reveal an increase in with frequency this wavelength range most Reliable also that the method preparation...
Ultra thin millimeter-wave absorbers on flexible polyimide substrate utilizing metamaterials are implemented for single and dual frequency bands in an emerging spectrum of 77, 95, 110 GHz. The band absorber is designed using a novel approach imbedding high resonator inside low capable absorbing electromagnetic energy at both 77 GHz simultaneously. total thickness the just 126 μm (almost 1/20th wavelength). Measured peak absorptions 92, 94, 99% 77.2, 94.8, 109.5 GHz, respectively, 92% 94% 109.8
It is no longer necessary to use extrapolated microwave dielectric values when designing millimeter-wave components and systems. Very recently, highly accurate (5- 1/2-mm) data on complex permittivity loss tangent have become available engineers for a variety of materials such as common ceramics, semiconductors, crystalline, glass materials. One quasi-optical measurement method has proved be most reproducible, namely, dispersive Fourier transform spectroscopy (DFTS) applied polarizing...
Our improved dispersive Fourier transform technique applied to a polarizing two-beam interferometer enables us provide high-precision continuous spectra of complex refractive index, dielectric permittivity, and loss tangent polyethylene, polypropylene, poly-4 methyl pentene-1 (TPX), polytetrafluorethylene, Plexiglas, acrylic, nylon over the frequency range 50–300 GHz. The first four are nonpolar polymers exhibit extremely low-loss characteristics. last three typical polar polymers, but they...
Highly accurate continuous spectra of the complex refractive index and dielectric permittivity are given in millimeter range for a variety potentially useful materials. The absorption coefficient is found to increase monotonically with increasing frequencies. Small amounts glassy inclusions or water were losses at all frequencies, but impurities radiation damage (except semiconductors) have not yet proved be detrimental performance. Materials been which millimeter-wave can tolerated when...
Complex permittivity of a number liquids and binary mixtures has been studied by measurement using the waveguide techniques at X Ku band.Particular pieces WR90 WR62 waveguides were designed for liquid materials.The custom TRL calibration kits are applied system.The measured results complex dielectrics, such as methanol, propyl alcohol, ethyl chlorobenzene, dioxane, cyclohexane mixtures, presented.Particular open-ended bands also holding data technique compared with those technique.Some...
The results of a measurement intercomparison aimed at assessing the systematic errors in near-millimetre-wavelength dielectric measurements on reasonably transparent solid specimens are presented and discussed. Various monochromatic, broad band, guided wave free space methods were intercompared frequency region from 30 to 900 GHz using round-robin refractive index absorption coefficient seven specimens. Typically, up 1% found results, while very much larger results.< <ETX...
A brief outline is given of the improvements which have been made in measurement techniques available for determination complex relative permittivity liquids and low-loss solids frequency range v = 100 GHz to 18 THz. These involve very stable interferometric systems with either dielectric beam splitters upper end or else free standing wire grid lower end, novel cell designs, use sensitive detectors, new computational procedures. The results can be checked by independent spot measurements...
There is a huge demand to accurately determine the magnetoelectrical properties of particles in nano-sized regime due modern IC technology revolution and biomedical applications. In this paper, we present microwave waveguide measurement technique for measuring complex permeability permittivity expensive magnetic powder materials. We used vector network analyzer provide standard TRL calibration free space inside measurements. order maintain recommended insertion phase range, very thin...
Metamaterial based electromagnetic wave absorbers provide perfect absorption only over a narrow bandwidth.In this paper, broadband response is achieved through embedding of one resonator inside another in each unit cell the metamaterial absorber lattice.These two resonators are oriented same direction to achieve reduced coupling between them realizing frequencies close other order broaden effective bandwidth.The paper presents such an at 77 GHz with bandwidth 8 and peak greater than 98%.The...
A simplified open resonator system is developed for the first time measurement of permittivity and loss tangent low-loss materials with high accuracy. In this new system, a cavity length variation technique quasioptical detection are implemented. The makes it possible to use only fixed frequency sources. employing lens refocusing an ultra sensitive liquid helium cooled detector allows us utilize one source in system. This novel open-resonator has much simpler structure, inexpensive provides...
An automated open resonator system was designed and constructed for precision measurement of the loss tangent dielectric permittivity low absorbing materials at 60 GHz. The use a high-Q hemispherical Fabry-Perot cavity together with highly stabilized synthesized phase-locked Gunn oscillator sources superheterodyne receiver made it possible to measure values as 10 mu rad. Both length variation frequency techniques were utilized provide precise data.< <ETX...
The complex refractive index spectrum of a solid material in the far infrared region ( approximately 5-500 cm-1) is determined from single dispersive interferometric measurement plane parallel specimen. This method uses essentially measured (frequency-dependent) transmission electromagnetic radiation through specimen and based on formalism developed by authors. especially suited for transparent solids, which are used as window materials far-infrared spectroscopic experiments. Results...
In this paper, we present a novel 2-18 GHz modified Archimedean polygonal spiral antenna that approximates circular in its highest frequencies and gradually transforms itself into square at lowest of operation. The design has successfully addressed the problem high axial ratios associated with ultra-wideband (UWB) rectangular systems. A low-profile, cavity backed model two variations original are presented study. Our results demonstrate demonstrates excellent ratio gain-bandwidth performance...
This paper presents accurate results for the complex permittivity, ε=ε′−jε″ and permeability, μ=μ′−jμ″ of barium ferrite powder (BaFe12O19) strontium (SrFe12O19), in frequency range from 8.0to26.5GHz. The permittivity permeability are determined via waveguide transmission/reflection (TR) technique cavity resonator (CR) at 25°C relative humidity &lt;75%. Measurements reveal that real permittivities BaFe12O19 SrFe12O19 are, respectively, 2.497&lt;εBa′&lt;2.678,...
Complex refractive index and complex dielectric permittivity loss tangent data for polyethylene, polypropylene, poly-4 methyl-perrtene1 (TPX), polytetrafluorethylene (Teflon) are presented over the frequency range 60-300 GHz. All of these nonpolar polymers extremely low-loss materials. As in microwave region, polyethylene demonstrates exceptionally characteristics entire millimeter-wave region. Polar such as nylon plexiglass exhibit much higher absorption (nearly an order magnitude higher)...
A new spectrometer for the precision measurement of dielectric permittivity and loss tangent is presented. The instrument capable providing high-resolution data first time over an extended W-band (68-118 GHz) frequency specimens with a large range absorption values, including highly absorbing that otherwise would not be possible. novel technique based on unbalanced bridge developed phase wave passed through specimen in free space (quasi-optical) reference provided by waveguide arm. Specially...
This paper investigates complex permittivity and permeability of several commercially available yttrium iron garnet (YIG) nickel-ferrite ceramics in the demagnetized state. The measurements were realized by using rectangular cavity resonators frequency range 4.5–26.5 GHz.
A new open-resonator technique is described for the determination of loss tangent and dielectric permittivity low-absorbing materials at 60 GHz. Micrometer stepping-motor-driven flat mirror in Fabry-Perot cavity call be scanned a very small step (to change length or spacing) to provide complete interferogram over entire resonance peak profile. This method termed here as new, full cavity-length variation technique. The minimum size 20 nm range about 25 mm, which can cover eight fundamental...