Contents
How do you choose a directional coupler?
The magnitude of the output signal of dual directional couplers should be equal to the magnitude at the input port minus the magnitude of the signal sampled by the coupler. An ideal directional coupler samples only a signal that is transmitted in a single direction.
How can directional coupler determine impedance?
– 32 dBm and the total power being measured at port 6 with 100 Ohms is the reflected power PR. Then the return loss is simply. RL=10log10(PT/PR) dB.
How do you create a coupler?
There are two ways of designing couplers: one using coupled transmission lines and the other using interconnected circuit elements consisting of independent transmission lines and or “lumped” elements like ideal capacitors, inductors, resistors, and transformers.
Which is the best directional coupler for VSWR?
Being directivity the most important parameter of a directional coupler used for reflection / VSWR measurement, it is very easy to characterize your coupler to know how good is in a particular frequency range. Out of these 3 couplers presented here, it is no surprise the higher cost DC1 clearly outperforms the other two in range.
What should the directivity of a coupler be?
The single most important parameter in a directional coupler used for reflection measurement is the Directivity. This parameter should be in these ranges to be useful: 10dB minimum for any minimally indicative measurement, no accuracy expected. 20dB minimum for reliable measurement.
What kind of circuit is used for VSWR detection?
The VSWR detection circuit, shown in Figure 6, consists of a directional coupler, a dual log detector, and a clamp circuit. The directional coupler between the HPA and the load couples a sample of incident and reflected waves on to the coupled and reflected ports, which are then fed to a dual log detector such as the ADL5519 or AD8302.
What’s the difference between SWR bridge and normal coupler?
The interesting difference about this coupler is that was produced as a SWR Bridge, and therefore the port connections come labelled as required for reflection measurement. That is not the case with standard directional couplers which comes labeled for normal coupler operation. SWR Bridge is a special case of Directional Coupler.