Can the reflection coefficient be complex?
If either ZL or Z0 are complex, the reflection coefficient (from (5) ) will in general be complex, meaning that there will be a phase shift (other than 180 degrees) in the reflected wave.
What does complex reflection coefficient mean?
(complex) reflection coefficient r is defined as. the ratio of the (complex) amplitudes of the. wave being sent back and the wave travelling. to the load at the point of reference (here x = 0): r r e.
What is a good reflection coefficient?
The value of an ideal VSWR is 1:1 or shortly expressed as 1. In this case the reflected power from the load to the source is zero.
What is the maximum value of reflection coefficient?
This is the ratio of reflected wave to incident wave at point of reflection. This value varies from -1 (for short load) to +1 (for open load), and becomes 0 for matched impedance load.
Is high return loss Good?
Return loss is a measure of how well devices or lines are matched. A match is good if the return loss is high. A high return loss is desirable and results in a lower insertion loss. From a certain perspective ‘Return Loss’ is a misnomer.
Can reflection coefficient zero?
3 (MARCH 1986); P. 736-741, 9 FIGS. At certain angles of incidence, the amplitude of a plane compressional wave reflected from a plane inter- face separating two solids is zero. No particular attention has been paid to zero reflection coefficients, nor to the param- eter combinations that produce them.
What is the acceptable range of reflection coefficient?
Reflection coefficient is the ratio of the reflected signal voltage to the incident signal voltage. The range of possible values for r is between zero and one. A transmission line terminated in its characteristic impedance will have all energy transferred to the load; zero energy will be reflected and r = 0.
How much return loss is too much?
While different systems have different acceptable return loss limits, 15 dB or better is a common system limit for a cable and antenna system.
What is considered good S11?
A good compromise is -13 dB. This is the origin of the rule of thumb, that the maximum acceptable value of S11 for an interconnect structure is about -13 dB: If S11 is smaller than -13 dB, we will not see the impact from these reflections on the transmitted signal.
Can reflection coefficient be more than 1?
You can of course have reflection coefficients larger than one if You allow line impedance to vary and the system is not terminated.
Is return loss positive or negative?
Return loss, which measures the amount of light reflected back toward the source, is also expressed in dBs and is always a positive number. A high return loss is a good thing and usually results in low insertion loss. Reflectance, which also measures reflection and is expressed in dB, is a negative number.
What is the ideal return loss?
The return loss scale is normally set up from 0 to 60 dB with 0 being an open or a short and 60 dB would be close to a perfect match.
How to calculate the complex reflection coefficient ( r )?
(complex) reflection coefficient r is defined as the ratio of the (complex) amplitudes of the wave being sent back and the wave travelling to the load at the point of reference (here x = 0): r re U U =⋅ =− + j def 0, 0, φ (6.1) This results in a spatial dependency for the complex amplitude of total voltageU(x) and total current I(x) according to
How is the phase of the reflection coefficient changed?
Note that the phase of the reflection coefficient is changed by twice the phase length of the attached transmission line. That is to take into account not only the phase delay of the reflected wave, but the phase shift that had first been applied to the forward wave, with the reflection coefficient being the quotient of these.
How to find the reflection coefficient of a load?
Typically, is established at the location of the load, where the impedance, ZL, is known. Then at any location zfollows from (1) solved for . With the magnitude and phase of established at the load, the reflection coefficient can be found at another location by a simple rotation through an angle 4(z/), as shown in Fig. 14.6.1b.
How is the reflection coefficient of a short circuit determined?
This implies the reflected wave having a 180° phase shift (phase reversal) with the voltages of the two waves being opposite at that point and adding to zero (as a short circuit demands). The reflection coefficient is determined by the load impedance at the end of the transmission line, as well as the characteristic impedance of the line.