O'Reilly logo

RF and Microwave Engineering: Fundamentals of Wireless Communications by Frank Gustrau

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

6.7 Power Divider

6.7.1 Wilkinson Power Divider

In the previous section we considered a non-reciprocal, loss-less three-port network that was matched at all ports. Now we introduce a three-port network that is matched at all ports, reciprocal but lossy: a power divider.

In Section 6.3.2 we looked at a simple power divider using two outgoing lines and a quarter-wave transformer for impedance matching at the input. The simple power divider was not matched at the output ports. With two quarter-wave transformers and a resistor R = 2Z0 we can design a power divider that is matched at all ports. Figure 6.34 shows the basic construction of a Wilkinson power divider.

Figure 6.34 Basic design of a Wilkinson power divider.

6.34

The power that is delivered to port 1 is split into equal parts and transferred to port 2 and port 3. Due to the symmetrical construction there is no voltage drop across the resistor R if the circuit is fed at port 1. Hence, there is no power loss in the resistor R. The resistor is only necessary to ensure the matching of port 2 and port 3.

The quarter-wave lines have characteristic impedances of images/c06_I0064.gif and transform the output impedances Z0 to input impedances of 2Z0. The parallel circuit of the two quarter-wave transformers at the input terminal leads to Zin, 1 = (2Z0||2

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required