COMPACT ULTRA-WIDEBAND WILKINSON POWER DIVIDER/COMBINER
Publication Date: 2017-Jul-06
The IP.com Prior Art Database
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Benito Lopez Keysight Technologies, Inc.
Wilkinson power dividers (WPDs) are widely used for splitting the power of an input signal into multiple outputs. A WPD is a bidirectional passive component that can also function as a power combiner in the reverse direction. Figure 1 shows a typical three-port WPD circuit with a pair of quarter-wave (λ/4) impedance transformers coupled together with a resistor that provides isolation between the output ports. Each pair of λ/4transformers and isolation resistor are referred to as a section. The conventional WPD shown in Figure 1 consists of a single section and has a usable bandwidth that is typically limited to f2/f1 = 1.44:1 for a voltage standing wave ratio (VSWR) < 1.22 and an isolation >20 dB.
A new class of multiple-section WPDs has been developed, providing an enormous improvement in VSWR and output isolation that cover a broader bandwidth. The theoretical design formulas for the multiple section WPD are described in detail in Reference . As the number of sections increase, the bandwidth capability improves. However, the increase in the number of sections typically results in larger physical size and poses a problem in printed circuit board (PCB) assemblies.
The present disclosure provides a low-cost compact design for an ultra-broadband power divider based on an eleven-section WPD, with capability to operate at 0.3 – 6 GHz (f2/f1 = 20:1). Figure 2 shows the circuit design of the WPD having eleven sections. Each of the sections is connected in series and has a respective pair of λ/4 transformers (Z) symmetrically coupled with an isolation resistor (R). The circuit design leverages curving lines for all the quarter-wave transformers (Z1 – Z11) instead of conventional straight lines to achieve higher compact physical layout having intrinsic dimensions of 2 cm × 4 cm.
In this exemplary embodiment, the substrate material of the PCB used is MEGTRON6 with nominal thickness of 0.55 mm. Computer simulation provides the optimized impedance values of the isolation resistors (R1 – R11) and the characteristic impedance of the λ/4 transformers (Z1 – Z11). The values are provided in Table 1....