POWER DIVIDERS provide a simple but important function in RF/ microwave systems: distributing signals as evenly as possible across a required operating frequency range. When designed eff ectively, a power divider can produce two or more outputs from an input signal with negligible loss or distortion to the signals, other than the expected dividing loss. For example: When dividing by two, each of the divided signal paths have onehalf as much power (or 3-dB less) than the original signal.
Of course, realworld circuits yield losses and other imperfections, meaning some amplitude and phase deviations will occur when signals are split through a power divider. But the passive power dividers from MECA Electronics among them, the two-way, 2-to- 18-GHz model 802-2-10.000aim for optimum performance over broad bandwidths. They do so by utilizing straightforward design approaches and quality manufacturing methods.
Model 802-2-10.000 (see figure) is a broadband example of the firm's powerdivider lines. These also include configurations with as many as 16 output ports as well as power combiners. In an application note (www.e-meca.com/tech_papers/why_dividers.php), the company points out that not all power dividers are truly reciprocal devices and can be used equally well in reverse, as power combiners. In the case of the model 802-2-10.000, it is designed for use as a power divider, with a single input port and two output ports, as well as 20-W input power-handling capability.
Under ideal conditions, such a power divider would accept input signals to 20 W and provide a pair of output signals to 10 W each. But in practical designs, loss will occur due to such things as connectors to printed-circuit-board (PCB) junctions and passive circuit elements even from dissipative losses from the PCB dielectric material.
In the model 802-2-10.000, these losses amount to typically 0.5 dB from 2 to 18 GHz, which will cause a slight drop in output power from the ideal maximum 10 W. The model 802- 2-10.000 two-way power divider achieves high isolation between its two output ports, with minimum isolation of 17 dB and typical isolation between output ports of 19 dB. The typical VSWR at its input and output ports is 1.50:1.
In comparing the quality of different power dividers, how well the output arms are balanced in terms of amplitude and phase characteristics provide some insight into the precision of the circuit design, as well as the quality of the manufacturing process. In the model 802-2- 10.000, the amplitude unbalance between output ports is minimized to a mere 0.3 dB, while the phase unbalance is held to a worst-case value of 5 deg. across the full 2-to-18-GHz frequency range.
Model 802-2-10.000 is designed for use across an operating temperature range of -55 to +85C. It is supplied in an aluminum housing equipped with stainlesssteel SMA connectors. For those needing less bandwidth, the company also offers model 802-2-11.500-M01, which keeps the maximum 20-W input rating across a bandwidth of 4 to 18 GHz. It exhibits maximum insertion loss of 0.5 dB across the full frequency range, with typical insertion loss of only 0.4 dB. The isolation between ports is 18 dB or better, and typically 20 dB. The power divider shows amplitude unbalance of 0.3 dB with phase unbalance of 6 deg. across the frequency range.
The maximum input VSWR is 1.40:1, with typical value of 1.30:1, while the maximum output VSWR is 1.35:1, with a typical output VSWR of 1.25:1. The model 802-2- 10.000 is supplied in an aluminum housing with stainless-steel SMA connectors.
The two power dividers are just two examples of the company's many lines of power dividers and power combiners, from 2-way through 16-way units. The firm also offers a wide range of other passive components, including power combiners, attenuators (including high-power Type N units rated for 150 W), bias tees, circulators/isolators, directional couplers, and terminations.
MECA ELECTRONICS, INC., 459 East Main St., Denville, NJ 07834; (866) 444-6322, (973) 625-0661, FAX: (973) 625-9277, www.e-meca.com.