scholarly journals 30 dB microstrip coupler with high directivity

2020 ◽  
Vol 2 (1) ◽  
pp. 26-33
Author(s):  
Azra Yildiz ◽  
Şehabeddin Taha İmeci
Keyword(s):  
Wide Band ◽  
Dielectric Substrate ◽  
Inhomogeneous Structure ◽  
Microwave Devices ◽  
Directional Couplers ◽  
Coupled Line ◽  
Almost All ◽  
Gap Coupling

Due to inhomogeneous structure of a microstrip directional couplers, i.e. partly dielectric substrate, partly air, they mostly present property of poor directivity and low coupling level. High directivity is achieved by a capacitive compensation by gap coupling of open stub formed in sub-coupled line. Neverthless, these couplers have advantage of easy fabrication, lightweight and incorporation with other microwave devices, and is validated via design using Sonnet software. The main goal was to obtain coupling around -30 dB, meaning that almost all power is passed to the output, with a wide band, from around 3.5GHz to nearly 9GHz. Desired values have been obtained, including isolation and input match reaching -70 dB.

Types and Areal Distribution of Ground Failure Associated with the 2019 Ridgecrest, California, Earthquake Sequence

2020 ◽  
Vol 110 (4) ◽  
pp. 1567-1578 ◽  
Author(s):  
Randall W. Jibson
Keyword(s):  
Epicentral Distance ◽  
Wide Band ◽  
Field Investigation ◽  
Earthquake Sequence ◽  
Lateral Spread ◽  
Fault Rupture ◽  
Rock Falls ◽  
Epicentral Area ◽  
Ground Failure ◽  
Almost All

ABSTRACT The July 2019 Ridgecrest, California, earthquake sequence included the largest earthquake (M 7.1) to strike the conterminous United States in the past 20 yr. To characterize the types, numbers, and areal distributions of different types of ground failure (landslides, liquefaction, and ground cracking), I conducted a field investigation of ground failure triggered by the sequence around the periphery of the epicentral area (which had limited access). The earthquake sequence triggered sparse and widely scattered landslides over an area of ∼22,000  km2 and at a maximum epicentral distance of 114 km; these metrics are within the upper bounds as compared with global averages for earthquakes of similar size. Some rock falls blocked primary and secondary roads, but no other landslide damage was reported. Almost all of the landslides in the peripheral area were small rock falls (∼1–10  m3), but a few larger (∼100  m3) rock slides also occurred. Though there are only informal reports about ground failure in the immediate epicentral area and we lack a detailed survey there, the small number (hundreds) and size of the landslides still seems to be far below global averages for M 7.1. This could be a result of the arid landscape and lack of a deeply weathered zone of soil and regolith. Liquefaction occurred along part of the western margin of Searles Valley. One large (∼0.4  km2) lateral spread caused by liquefaction severely damaged parts of Trona. Minor liquefaction also occurred in a ∼100-m-wide band along the fault-rupture zone in some places.

Approach to the design of slot-coupled-line directional couplers

2015 ◽  
Author(s):  
Jakub Sorocki ◽  
Ilona Piekarz ◽  
Izabela Slomian ◽  
Krzysztof Wincza ◽  
Slawomir Gruszczynski
Keyword(s):  
Directional Couplers ◽  
Coupled Line

Computation of wide-band waveguide directional couplers

1963 ◽  
Vol 6 (3) ◽  
pp. 249-253
Author(s):  
A. N. Akhiezer
Keyword(s):  
Wide Band ◽  
Directional Couplers

scholarly journals DEVELOPMENT AND OPTIMIZATION OF AN ULTRA WIDEBAND MINIATURE MEDICAL ANTENNA FOR RADIOMETRIC MULTI-CHANNEL MULTI-FREQUENCY THERMAL MONITORING

2020 ◽  
pp. 71-81
Author(s):  
Mikhail Sedankin ◽  
Vitaly Leushin ◽  
Alexander Gudkov ◽  
Igor Sidorov ◽  
Sergey Chizhikov ◽  
...  
Keyword(s):  
Radiation Power ◽  
Fdtd Method ◽  
Depth Resolution ◽  
Wide Band ◽  
Biological Tissues ◽  
Dielectric Substrate ◽  
Ultra Wideband ◽  
Antenna Design ◽  
Design Parameters ◽  
Calculated Mass

The article is devoted to the development of a printed ultra-wideband miniature antenna that can be used for microwave radiometry. An antenna design with a ring-shaped radiator has been proposed, which provides reception of microwave radiation from biological tissues in the 1800–4600 MHz range. The results of mathematical modeling of the antenna electromagnetic field in biological tissues using the finite difference time domain (FDTD) method are presented. Optimization of the antenna design has been carried out to ensure acceptable matching parameters and optimal antenna functionality. The developed antenna has a height of 6 mm and a calculated mass of 5 g; it is planned to manufacture a dielectric substrate based on PDMS polymer with the addition of barium titanate. The issues of calculating the antenna parameters (measurement depth, resolution and distribution of radiation power over the volume of biological tissue, sensitivity, etc.) are considered. The research results and design parameters of the developed antenna demonstrated the effectiveness of the new antenna and the possibility of its adaptation to the object of research. Considering the presence of an ultra-wide band and miniature dimensions, the antenna can be a sensor of a multi-frequency multi-channel microwave radiothermograph

Sign in / Sign up

Export Citation Format

Share Document