www.radartutorial.eu Radar Basics

“Balanced Duplexer”

Duplexer using λ /4- stubs have a relatively small bandwith caused of the frequency depended length of the stubs. This is very impractical by existing electronic jamming on a particular frequency.

Radar sets working on a wider frequency band, need a duplexer with a wider bandwith e.g. the “Balanced Duplexer”. This duplexer works in accordance with the following principle:

from
transmitter
to the receiver
spark gaps
to antenna
dummy load

Figure 1: Principle of a “Balanced Duplexer”

transmitter
receiver
spark gaps
to antenna
dummy load

Figure 1: Principle of a “Balanced Duplexer”

During reception the amplitude of the received echo is not sufficient to cause an arc across either spark gap. both parts of the received echo can pass the spark gaps. The echoes recur both hybrides and accumulate their parts in-phase. The loss of this duplexer is about 0.5 to 1.5 dB.