Wilkinson power dividers, also known as splitters, are essential components in RF and microwave circuits. These devices are used to divide or split a single input power signal into multiple output power signals with equal amplitudes.
The Wilkinson power divider operates on the principle of utilizing a transmission line network to achieve effective power division. The design consists of a microstrip structure, which is a thin strip of conducting material mounted on a dielectric substrate.
This power divider can be used in both directions – i.e. as a Power Splitter and as a Combiner. As well it can have any number of ports.
The primary advantage of the Wilkinson power divider lies in its simplicity and low insertion loss characteristics. The divider is able to achieve isolation between the output ports while maintaining a matched condition on all ports.
It offers excellent power division across a broad range of frequencies, making it suitable for applications in communication systems, radar systems, and high-frequency measurement systems.
Additionally, these power dividers provide good RF isolation between the output ports, ensuring minimal interference or coupling between the signals. The resistor network within the Wilkinson power divider helps maintain impedance matching and minimizes reflections.
Another advantage of this divider is that it can be fabricated on a printed circuit board at very low cost. The transmission line elements can be easily etched on to the PCB with no additional component costs.
Overall, the Wilkinson power divider is a reliable and efficient tool for dividing power signals in various RF and microwave applications.
One of the main disadvantages is that the Wilkinson divider does not have wide bandwidth. This is due to the fact that it is constructed from quarter wave transmission lines.
At lower frequencies the dimensions of the quarter wavelength transmission lines can be quite large thereby limiting its application to higher frequencies. (Recall the lower the frequency, the larger the wavelength and therefore dimensions). Even at high frequencies, the space requirements on a PCB might be disadvantageous when there are limitations on total size.
The main purpose of a Wilkinson divider is to evenly distribute the power of the input signal among the output ports.
This is useful in various applications where multiple signal paths or channels are required. For example, in telecom systems, a Wilkinson divider can be used to split an input signal into multiple outputs that go to different antennas or base stations.
It can also be used in measurement systems to divide a signal that needs to be simultaneously routed to multiple instruments or sensors. Additionally, Wilkinson dividers are commonly used in the design of microwave amplifiers and filters to provide equal power splitting and distribution among different components. Overall, Wilkinson dividers play a crucial role in many electronic systems that require signal splitting and distribution.
What are the differences between Wilkinson and Resistive power divider?
The picture below shows both a Resistive power divider and a Wilkinson Power divider
In a resistive power divider, both output signals are at the same level and 6 dB lower than the input signal. By comparison, in Wilkinson power dividers, the output signals are 3 dB below the input signal. More signal loss in the case of the resistive divider.
Resistive dividers can operate down to DC. Wilkinson dividers are limited to hundreds of Megahertz at the low end. Therefore they are not suited for low frequency applications.
This is a measure of how much signal from one of the output ports couples on to the other. A lower level of isolation (higher dB value) is more desirable. Wilkinson dividers typically offer 20 dB isolation while resistive splitters have only 6 dB of isolation.