Transmission-line impedance measurement at microwave frequencies

1973 ◽  
Vol 19 (15) ◽  
pp. 363
Author(s):  
J.W. Gould
Keyword(s):  
Transmission Line ◽  
Impedance Measurement ◽  
Microwave Frequencies

scholarly journals Broadband transmission-line illusions based on transformation electromagnetic

2019 ◽  
Vol 6 ◽  
pp. 23
Author(s):  
Tsutomu Nagayama ◽  
Atsushi Sanada
Keyword(s):  
Transmission Line ◽  
Incident Angle ◽  
Near Field ◽  
Homogeneous Medium ◽  
Field Measurements ◽  
Dielectric Substrate ◽  
Frequency Range ◽  
Microwave Frequencies ◽  
Intrinsic Nature ◽  
Line Technology

We demonstrate broadband transmission-line illusions based on transformation electromagnetics at microwave frequencies by using the distributed full-tensor anisotropic medium. Due to an intrinsic nature of the non-resonant unit cell of the medium, the illusions operate from DC to an upper limit frequency where the homogeneous medium approximation holds. Two-dimensional groove and bump illusion media mimicking scattered waves by an original groove and a bump are designed. Their broadband and incident angle independent operations are confirmed by circuit simulations. The groove illusion medium is implemented on a dielectric substrate with microstrip-line technology, and it is confirmed experimentally by near-field measurements that the illusion medium well mimics scattered waves by the original groove in the broadband frequency range from 2.60 GHz to 4.65 GHz.

scholarly journals Smaller-loss planar SPP transmission line than conventional microstrip in microwave frequencies

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Hao Chi Zhang ◽  
Qian Zhang ◽  
Jun Feng Liu ◽  
Wenxuan Tang ◽  
Yifeng Fan ◽  
...  
Keyword(s):  
Transmission Line ◽  
Microwave Frequencies

scholarly journals Distance Relay Protection Improvement of Alaoji-Afam 330kV Transmission Line

2018 ◽  
Vol 3 (9) ◽  
pp. 40
Author(s):  
Eseosa Omorogiuwa ◽  
Wonodi Ikonwa
Keyword(s):  
Transmission Line ◽  
Impedance Measurement ◽  
Relay Protection ◽  
Distance Relay ◽  
Fault Resistance ◽  
Good Improvement ◽  
Distance Relays ◽  
Protected Zone

Fault resistance influences the operation of distance relays, thus causing it to give inaccurate impedance measurement, thus resulting to under-reach condition. .Trip report of fault occurrence in Alaoji-Afam 330kV line showed the effect of fault resistance on the relay operation. This paper seek to improve distance relay performance in terms of reliability, speed and selectivity on Alaoji-Afam 330kV transmission line, when fault resistance is present through adjustment of protected zone reach using NEPLAN software to model and simulate distance relay used for this study. Several simulations were run and the results showed good improvement of distance relay operation in handling fault conditions. Adjustment of the protected zone reach was done to compensate for the effect of high fault resistance on distance relay operation.

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