Design and performance of an open-ended converging microwave antenna in fracturing biotite diorite at low microwave power levels

Microwave imaging is the technique to identify hidden objects from structures using electromagnetic waves that can be applied in medical diagnosis. The change of dielectric property can be detected using microwave antenna sensor, which can lead to localization of abnormality in the human body. This paper presents a stacked type modified Planar Inverted F Antenna (PIFA) as microwave imaging sensor. Design and performance analysis of the sensor antenna along with computational and experimental analysis to identify concealed object has been investigated in this study. The dimension of the modified PIFA radiating patch is 40 × 20 × 10 mm3. The reflector walls used, are 45 mm in length and 0.2-mm-thick inexpensive copper sheet is considered for the simulation and fabrication which addresses the problems of high expenses in conventional patch antenna. The proposed antenna sensor operates at 1.55–1.68 GHz where the maximum realized gain is 4.5 dB with consistent unidirectional radiation characteristics. The proposed sensor antenna is used to identify tumor in a computational human tissue phantom based on reflection and transmission coefficient. Finally, an experiment has been performed to verify the antenna’s potentiality of detecting abnormality in realistic breast phantom.

Download Full-text

Producibility and performance of the microwave power HBT

GaAs IC Symposium Technical Digest 1992 ◽

10.1109/gaas.1992.247271 ◽

2003 ◽

Cited By ~ 7

Author(s):

W.J. Ho ◽

N.L. Wang ◽

M.F. Chang ◽

J.A. Higgins

Keyword(s):

Microwave Power ◽

And Performance

Download Full-text

HBTs FOR MICROWAVE POWER APPLICATIONS

International Journal of High Speed Electronics and Systems ◽

10.1142/s0129156494000140 ◽

1994 ◽

Vol 05 (03) ◽

pp. 275-348

Author(s):

BURHAN BAYRAKTAROGLU ◽

J. AIDEN HIGGINS

Keyword(s):

Electronic Properties ◽

Microwave Power ◽

High Performance ◽

Microwave Devices ◽

Rapid Progress ◽

Performance Improvements ◽

The Status ◽

Military Systems ◽

And Performance ◽

Made In

The status of the microwave power HBT is reviewed. The rapid progress made in this technology is fueled by the need for high performance transmitter amplifiers, advanced military systems and supported by the favorable electronic properties of the device. A survey of the device design and fabrication techniques indicates that the technology has not yet reached its limit; further advances are possible and performance improvements will continue. The power and efficiency of GaAs HBTs are now competitive with the most advanced microwave devices in the 1–20 GHz range.

Download Full-text

Transmission Scanning Electron Microscopy and Energy Analysis with the Siemens ELMISKOP 101

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100095509 ◽

1972 ◽

Vol 30 ◽

pp. 450-451

Author(s):

H. M. Thieringer

Keyword(s):

Objective Lens ◽

Transmission Microscopy ◽

Image Recording ◽

Mode Of Operation ◽

Scanning Transmission ◽

Electron Microscopes ◽

And Performance ◽

Convergent Beam ◽

Ray Path ◽

Beam Diffraction

It has repeatedly been show that with conventional electron microscopes very fine electron probes can be produced, therefore allowing various micro-techniques such as micro recording, X-ray microanalysis and convergent beam diffraction. In this paper the function and performance of an SIEMENS ELMISKOP 101 used as a scanning transmission microscope (STEM) is described. This mode of operation has some advantages over the conventional transmission microscopy (CTEM) especially for the observation of thick specimen, in spite of somewhat longer image recording times.Fig.1 shows schematically the ray path and the additional electronics of an ELMISKOP 101 working as a STEM. With a point-cathode, and using condensor I and the objective lens as a demagnifying system, an electron probe with a half-width ob about 25 Å and a typical current of 5.10-11 amp at 100 kV can be obtained in the back focal plane of the objective lens.

Download Full-text

Angular Resolved Electron Spectroscopy with Parallel Recording

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100135459 ◽

1990 ◽

Vol 48 (2) ◽

pp. 370-371

Author(s):

Huang Min ◽

P.S. Flora ◽

C.J. Harland ◽

J.A. Venables

Keyword(s):

Electron Spectroscopy ◽

Low Voltage ◽

Solid Angle ◽

Detection System ◽

Voltage Electron ◽

Cylindrical Mirror ◽

Inner Radius ◽

Channel Plate ◽

And Performance ◽

Type Detector

A cylindrical mirror analyser (CMA) has been built with a parallel recording detection system. It is being used for angular resolved electron spectroscopy (ARES) within a SEM. The CMA has been optimised for imaging applications; the inner cylinder contains a magnetically focused and scanned, 30kV, SEM electron-optical column. The CMA has a large inner radius (50.8mm) and a large collection solid angle (Ω > 1sterad). An energy resolution (ΔE/E) of 1-2% has been achieved. The design and performance of the combination SEM/CMA instrument has been described previously and the CMA and detector system has been used for low voltage electron spectroscopy. Here we discuss the use of the CMA for ARES and present some preliminary results.The CMA has been designed for an axis-to-ring focus and uses an annular type detector. This detector consists of a channel-plate/YAG/mirror assembly which is optically coupled to either a photomultiplier for spectroscopy or a TV camera for parallel detection.

Download Full-text

Novel epoxy/anhydride alternatives for biological electron microscopy: Physical and performance characteristis of embed 812 and LX 112 in combination with NSA/NMA/DMAE

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100156985 ◽

1989 ◽

Vol 47 ◽

pp. 1000-1001

Author(s):

Joe A. Mascorro ◽

Gerald S. Kirby

Keyword(s):

Electron Microscopy ◽

Flow Rate ◽

Succinic Anhydride ◽

Volume Flow Rate ◽

Mass Density ◽

Uranyl Acetate ◽

Volume Flow ◽

Base Resin ◽

And Performance ◽

Acid Anhydrides

Embedding media based upon an epoxy resin of choice and the acid anhydrides dodecenyl succinic anhydride (DDSA), nadic methyl anhydride (NMA), and catalyzed by the tertiary amine 2,4,6-Tri(dimethylaminomethyl) phenol (DMP-30) are widely used in biological electron microscopy. These media possess a viscosity character that can impair tissue infiltration, particularly if original Epon 812 is utilized as the base resin. Other resins that are considerably less viscous than Epon 812 now are available as replacements. Likewise, nonenyl succinic anhydride (NSA) and dimethylaminoethanol (DMAE) are more fluid than their counterparts DDSA and DMP- 30 commonly used in earlier formulations. This work utilizes novel epoxy and anhydride combinations in order to produce embedding media with desirable flow rate and viscosity parameters that, in turn, would allow the medium to optimally infiltrate tissues. Specifically, embeding media based on EmBed 812 or LX 112 with NSA (in place of DDSA) and DMAE (replacing DMP-30), with NMA remaining constant, are formulated and offered as alternatives for routine biological work.Individual epoxy resins (Table I) or complete embedding media (Tables II-III) were tested for flow rate and viscosity. The novel media were further examined for their ability to infilftrate tissues, polymerize, sectioning and staining character, as well as strength and stability to the electron beam and column vacuum. For physical comparisons, a volume (9 ml) of either resin or media was aspirated into a capillary viscocimeter oriented vertically. The material was then allowed to flow out freely under the influence of gravity and the flow time necessary for the volume to exit was recored (Col B,C; Tables). In addition, the volume flow rate (ml flowing/second; Col D, Tables) was measured. Viscosity (n) could then be determined by using the Hagen-Poiseville relation for laminar flow, n = c.p/Q, where c = a geometric constant from an instrument calibration with water, p = mass density, and Q = volume flow rate. Mass weight and density of the materials were determined as well (Col F,G; Tables). Infiltration schedules utilized were short (1/2 hr 1:1, 3 hrs full resin), intermediate (1/2 hr 1:1, 6 hrs full resin) , or long (1/2 hr 1:1, 6 hrs full resin) in total time. Polymerization schedules ranging from 15 hrs (overnight) through 24, 36, or 48 hrs were tested. Sections demonstrating gold interference colors were collected on unsupported 200- 300 mesh grids and stained sequentially with uranyl acetate and lead citrate.

Download Full-text

Trace nanoanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100172437 ◽

1994 ◽

Vol 52 ◽

pp. 940-941

Author(s):

D. E. Newbury ◽

R. D. Leapman

Keyword(s):

High Performance ◽

Secondary Ion Mass Spectrometry ◽

Detection Efficiency ◽

Volume Element ◽

And Performance ◽

Trace Constituents ◽

Secondary Ion ◽

Concentration Levels ◽

Structure Properties

Trace constituents, which can be very loosely defined as those present at concentration levels below 1 percent, often exert influence on structure, properties, and performance far greater than what might be estimated from their proportion alone. Defining the role of trace constituents in the microstructure, or indeed even determining their location, makes great demands on the available array of microanalytical tools. These demands become increasingly more challenging as the dimensions of the volume element to be probed become smaller. For example, a cubic volume element of silicon with an edge dimension of 1 micrometer contains approximately 5×1010 atoms. High performance secondary ion mass spectrometry (SIMS) can be used to measure trace constituents to levels of hundreds of parts per billion from such a volume element (e. g., detection of at least 100 atoms to give 10% reproducibility with an overall detection efficiency of 1%, considering ionization, transmission, and counting).

Download Full-text