Delay-Sum Group Delay Controller With Low-Loss and Low-Phase Variation

This paper presents a new shape (s-shape monopole) of a super wideband antenna using stepped meander lines, a quarter waveguide transformer feeding line, and a defected ground structure (DGS). The antenna will be used for multiple wireless communication applications like WIMAX/WLAN/ISM/UWB, and also for several wireless communication applications. The total dimensions of the proposed antenna are 35 mm × 35 mm × 1.57 mm or 0.36 λo × 0.36 λo × 0.016 λo, which are the corresponding electrical dimensions with free-space wavelength (λo) at the lower operating frequency. The antenna is designed and simulated into two steps: the first (Antenna 1) covers a bandwidth of 18.2 GHz, while the second (Antenna 2, using DGS) covers a super wide bandwidth of 37.82 GHz (3.08–40.9 GHz). The measured fractional bandwidth and bandwidth ratio of the antenna are 174.68% and 13.009:1, respectively, which is operating from 3.09–40.2 GHz. The maximum calculated gain and efficiency are 5.9 dBi and 92.7%, respectively. The time-domain performance is good due to the calculation of the system fidelity factor, group delay, and its linear and constant phase variation.

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A LOW-LOSS DUAL-BAND NEGATIVE GROUP DELAY CIRCUIT WITH FLEXIBLE DESIGN

Progress In Electromagnetics Research Letters ◽

10.2528/pierl21041701 ◽

2021 ◽

Vol 98 ◽

pp. 33-40

Author(s):

Yuwei Meng ◽

Zhongbao Wang ◽

Yu Bai ◽

Shao-Jun Fang ◽

Hongmei Liu

Keyword(s):

Group Delay ◽

Dual Band ◽

Negative Group ◽

Flexible Design ◽

Low Loss ◽

Delay Circuit ◽

Negative Group Delay

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Observation of ∼20 ns group delay in a low-loss apodized fiber Bragg grating

Optics Letters ◽

10.1364/ol.39.003978 ◽

2014 ◽

Vol 39 (13) ◽

pp. 3978 ◽

Cited By ~ 10

Author(s):

George Skolianos ◽

Martin Bernier ◽

Réal Vallée ◽

Michel J. F. Digonnet

Keyword(s):

Fiber Bragg Grating ◽

Group Delay ◽

Bragg Grating ◽

Low Loss

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Low-Loss Images in a Stem/Tem Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009244x ◽

1976 ◽

Vol 34 ◽

pp. 496-497 ◽

Cited By ~ 1

Author(s):

David C. Joy ◽

Dennis M. Maher

Keyword(s):

High Resolution ◽

Surface Topography ◽

Beam Direction ◽

Low Loss ◽

Specimen Holder ◽

Glancing Angle ◽

High Resolution Images ◽

Set Up ◽

Conventional Manner ◽

Objective Type

High-resolution images of the surface topography of solid specimens can be obtained using the low-loss technique of Wells. If the specimen is placed inside a lens of the condenser/objective type, then it has been shown that the lens itself can be used to collect and filter the low-loss electrons. Since the probeforming lenses in TEM instruments fitted with scanning attachments are of this type, low-loss imaging should be possible.High-resolution, low-loss images have been obtained in a JEOL JEM 100B fitted with a scanning attachment and a thermal, fieldemission gun. No modifications were made to the instrument, but a wedge-shaped, specimen holder was made to fit the side-entry, goniometer stage. Thus the specimen is oriented initially at a glancing angle of about 30° to the beam direction. The instrument is set up in the conventional manner for STEM operation with all the lenses, including the projector, excited.

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Edge Penetration Effects in the Low-Loss Electron Image in the SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103097 ◽

1988 ◽

Vol 46 ◽

pp. 202-203

Author(s):

Oliver C. Wells

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Beam Energy ◽

Secondary Electron ◽

Sharp Edge ◽

Beam Diameter ◽

Low Loss ◽

Additional Information ◽

Electron Image ◽

Scanning Electron

The low-loss electron (LLE) image in the scanning electron microscope (SEM) is useful for the study of uncoated photoresist and some other poorly conducting specimens because it is less sensitive to specimen charging than is the secondary electron (SE) image. A second advantage can arise from a significant reduction in the width of the “penetration fringe” close to a sharp edge. Although both of these problems can also be solved by operating with a beam energy of about 1 keV, the LLE image has the advantage that it permits the use of a higher beam energy and therefore (for a given SEM) a smaller beam diameter. It is an additional attraction of the LLE image that it can be obtained simultaneously with the SE image, and this gives additional information in many cases. This paper shows the reduction in penetration effects given by the use of the LLE image.

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