Antenna splitter
Antenna splitters have the task of connecting several high-frequency sources or sinks with one connector with the correct impedance and, if necessary, the correct phase. In contrast to voltage matching (example: 230 V voltage sources), multiple sources or sinks can not simply be connected in parallel with impedance matching .
Designations
Depending on the task, technically similar circuits are also given completely different names:
- Power dividers are used, for example, to combine several less powerful output stages into a single, correspondingly more powerful output stage.
- Antenna distributors or antenna splitters are used either in group antennas to interconnect several partial antennas or to connect several receivers to one antenna.
- Signal splitters or RF distributors are more generic names for such circuits.
use
Antenna splitters can be realized in different ways:
- Resistor networks are often used in antenna distribution systems in order to minimize the effect of the branches on the main line. This is how z. B. the television antenna sockets in apartment buildings.
- Transformers ensure the impedance matching between an input and several outputs of the same impedance . A transformer with a (voltage) transmission ratio of 2: 1 can convert 50 Ω at the input into 12 Ω at the output. Four 50 Ω connections can then be connected in parallel there. There are quite complex schemes here, e.g. B. to force an even distribution of power.
- In narrowband systems, λ / 4-long line sections are often used for impedance transformation. In this case, (input impedance × output impedance) = line impedance × 2.
- The use of hybrids makes it possible to separate the forward and reverse waves. This enables units to be interconnected without any repercussions from the other units or the common output or input.