Equipment Type; Functions And Features; Working Principle; Interfaces - Huawei OptiX RTN 600 ODU Manual

2 Hybrid Coupler

2.1 Equipment Type

The hybrid coupler is classified into two types, namely, 3 dB balanced hybrid coupler and 6 dB
unbalanced hybrid coupler.
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2.2 Functions and Features

The hybrid coupler is used to combine and split RF signals.
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2.3 Working Principle

A hybrid coupler consists of a waveguide cavity-.
The waveguide cavity is the major part of a hybrid coupler. It has three ports. They are the
common interface, primary branch interface, and secondary branch interface.
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2.4 Interfaces

The hybrid coupler has three types of interfaces: antenna interface, primary branch interface,
and secondary branch interface.
The hybrid couplers are classified into the hybrid coupler with waveguide interfaces and the
hybrid coupler with coaxial interfaces according to the type of the branch interfaces of the hybrid
coupler. The ODUs with waveguide interfaces use the hybrid couplers with waveguide
interfaces, and the ODUs with coaxial interfaces use the hybrid couplers with coaxial interfaces.
The antenna interfaces of the 7-38 GHz ODUs are waveguide interfaces, and the antenna
interfaces of the 6 GHz SPA ODUs are coaxial interfaces.
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A 3 dB balanced hybrid coupler can split one RF signal into two RF signals that have almost
the same power. In other words, each of the two RF signals is attenuated about 3 dB,
compared with the original RF signal.
A 6 dB unbalanced hybrid coupler can split one RF signal into two RF signals that have
different power. The RF signal that has the smaller power is attenuated about 6 dB,
compared with the original RF signal.
In the transmit direction, the hybrid coupler combines two ODU RF signals into one RF
signal which is then transmitted to the antenna.
In the receive direction, the hybrid coupler divides the RF signal received from the antenna
into two RF signals which are then transmitted to the ODU.
In the transmit direction, the RF signals received by the two branch interfaces are combined
into one in the waveguide cavity, which is then output through the common interface.
In the receive direction, the RF signal received by the common interface are divided into
two RF signals in the waveguide cavity, which are then output through the two branch
interfaces.
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OptiX RTN 600 ODU
Hardware Description
Issue 06 (2010-05-30)