 # Question: What Is A Good Return Loss?

## How can insertion loss be reduced?

Fixing links that have failed insertion loss normally involves reducing the length of the cabling by removing any slack in the cable run.

Excessive insertion loss can also be caused by poorly terminated connectors / plugs.

A poor connection can add significant insertion loss..

## What causes return loss?

There are two major causes of RL in a network: discontinuities and impedance mismatches. Discontinuities occur at connections where cable is terminated to plugs or jacks and within the plug/jack connection itself. A discontinuity can also occur if a cable is bent too much, kinked or otherwise damaged.

## Is s11 return loss?

S11 represents how much power is reflected from the antenna, and hence is known as the reflection coefficient (sometimes written as gamma: or return loss. If S11=0 dB, then all the power is reflected from the antenna and nothing is radiated.

## What is the difference between insertion loss and return loss?

This power is the incident power. … The ratio of incident power to transmitted power, in dB terminology, is the insertion loss. The ratio of incident power to the reflected power, in dB terminology, is the return loss.

## How is s11 calculated?

S11 = b1/a1 for a2= 0 or Zl=Zo. This is an input reflection coefficient. S11 is equal to the ratio of a reflected wave and an incident wave with Zl=Zo. Thus, S11 can be plotted on a Smith chart and the input impedance of the two-port device can be found immediately.

## How does antenna reduce return loss?

The return loss is minimized by designing moderate substrate height between the ground plane and radiating patch about 4 mm. antenna. Finally a finite large enough ground plane is design to support the patch.

## Why 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. Return loss is used in modern practice in preference to SWR because it has better resolution for small values of reflected wave.

## 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.

## Why return loss should be less than 10 dB?

S11 is return loss of device, this parameter measures how much input power given to device is reflected back at input port. … S11 below -10dB means at least 90% input power is delivered to device and reflected power is less than 10%. This value is sufficient for many applications.

## What is output return loss?

In the small signal, linear environment, output return loss, also referred to as output VSWR or S22, is an important parameter in determining how much signal will be delivered to the load, in calculating the stability of an amplifier stage, and in determining how much insertion gain ripple might be expected when …

## What is s11 s12 s21 s22?

S11 is the input port voltage reflection coefficient. S12 is the reverse voltage gain. S21 is the forward voltage gain. S22 is the output port voltage reflection coefficient. The S-parameter matrix can be used to determine reflection coefficients and transmission gains from both sides of a two port network.

## What is VSWR formula?

A ratio of infinity to one occurs when the load is an open circuit. A ratio of 1:1 occurs when the load is perfectly matched to the transmission-line characteristic impedance. VSWR is defined from the standing wave that arises on the transmission line itself by: VSWR = |VMAX|/|VMIN|

## What is VSWR and return loss?

The VSWR is a measure of the standing waves set up in a feeder as a result of a mismatch, whereas the return loss looks at the amount of power absorbed by a load when power from a source is sent to it. The return loss being the difference between the incident power and the reflected.

## What is an acceptable VSWR?

A VSWR of less than 1.5:1 is ideal, a VSWR of 2:1 is considered to be marginally acceptable in low power applications where power loss is more critical, although a VSWR as high as 6:1 may still be usable with the right equipment.

## Can VSWR be negative?

In this case the VSWR will be 1:1 and the voltage and the current will be constant over the whole length of the feed line. Return loss is a measure in dB of the ratio of power in the incident wave to that in the reflected wave, and we define it to have a negative value.