Condition for reflection coefficient magnitude greater than one for passive transmission line and passive load

1981 ◽  
Vol IM-30 (3) ◽  
pp. 230-231 ◽  
Author(s):  
P. I. Somlo ◽  
J. D. Hunter
Keyword(s):  
Reflection Coefficient ◽  
Transmission Line

scholarly journals Study and analysis of discontinuity by using taper baluns

2015 ◽  
Vol 4 (2) ◽  
pp. 283
Author(s):  
Hussein Aldahhan ◽  
Bashar Qas Elias
Keyword(s):  
Reflection Coefficient ◽  
Transmission Line ◽  
Insertion Loss ◽  
Power Flow ◽  
Microstrip Line ◽  
Return Loss ◽  
Wide Band ◽  
Coplanar Stripline ◽  
Insertion Losses

A coplanar stripline (CPS) to microstrip line transition (MSL) are designed with high characteristics, such as wide band, low return loss and high insertion loss. Two types of tapers are proposed, exponential and triangular to decreases of discontinuity in the power flow in transmission line. The suggested design achieved reflection coefficient under -10 dB over wide band from 1 GHz to 3 GHz and insertion losses of less than 1 dB.

scholarly journals Broadband Dipole-Loop Combined Nanoantenna Fed by Two-Wire Optical Transmission Line

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Janilson L. de Souza ◽  
Karlo Q. da Costa ◽  
Victor Dmitriev ◽  
Felipe Bamberg
Keyword(s):  
Reflection Coefficient ◽  
Transmission Line ◽  
Radiation Pattern ◽  
Method Of Moments ◽  
Input Impedance ◽  
Optical Transmission ◽  
Near Field ◽  
Impedance Matching ◽  
Linear Method ◽  
Geometrical Parameters

This paper presents a broadband nanoantenna fed by a two-wire optical transmission line (OTL). The antenna is defined by a combination of a dipole and a loop, where only the dipole element is connected to the OTL. The analysis is fulfilled by the linear method of moments with equivalent surface impedance to model the conductors. Firstly, the nanoantenna alone is investigated, where the input impedance, current distribution, reflection coefficient, fractional bandwidth, radiation efficiency, and radiation pattern are analyzed. Then, the input impedance matching of this antenna with the OTL is considered. In this case the current, near field distribution, radiation pattern, and reflection coefficient are calculated for different geometrical parameters. The results show that the loop inserted in the circuit can increase the bandwidth up to 42% and decreases the reflection coefficient in the OTL to −25 dB.

scholarly journals QUADRATURE MEASUREMENT METHOD FOR COMPLEX PARAMETERS OF MICROWAVE TWO-POLES

2019 ◽  
pp. 29-38 ◽  
Author(s):  
Yu. B. Gimpilevich ◽  
S. E. Zebek
Keyword(s):  
Reflection Coefficient ◽  
Transmission Line ◽  
Measurement Errors ◽  
Frequency Conversion ◽  
Phase Distribution ◽  
Reference Signal ◽  
Microwave Oscillation ◽  
Synchronous Detection ◽  
Complex Reflection Coefficient ◽  
Complex Reflection

A new method based on direct frequency conversion is developed for measuring complex reflection coefficient of microwave two-poles. The method is based on the use of quadrature synchronous detection of the signal branched by omnidirectional probe with subsequent quadrature processing of the detected signal components. Such approach makes it possible to solve measuring task by simultaneously analyzing both amplitude and phase distribution of the field in transmission line which leads to redundancy. In addition, the use of direct frequency conversion provides the detection linearity in considerably higher dynamic range of the levels of the signal forwarded from the transmission line. So, both of these factors can improve the measurement accuracy. The method is performed by excitation of probing harmonic microwave oscillation in transmission line and formation of reference microwave oscillation with the same frequency. The reference signal and the signal branched from the transmission line by omnidirectional mobile probe are fed to the inputs the quadrature synchronous detector. At its outputs, I and Q components of the detected signal are formed. By means of these components, the amplitude and phase field distribution in the trans-mission line is obtained. It is followed by calculation of module and phase estimations using the expressions presented in the paper. The measurement result is obtained as arithmetic average of these estimations. A mathematical model of the proposed method is developed. The relations for the module and phase of the complex reflection coefficient are derived based on the analysis of both the amplitude and phase distribution of electromagnetic field in the transmission line. The paper describes the experimental unit in the form of vector measuring line that implements the quadrature method of measurement. The experimental analysis of the amplitude and phase distribution of the field in microwave path is carried out for standard loads with different parameters. Based on the analysis results, the estimations of measured parameters are calculated and measurement errors are defined. It is shown that highprecision measuring instruments can be designed using the proposed method.

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