wilkinson power summator–divider
K. Ya. Aubakirov, V.I. Govorukhin, L.G. Plavsky, M.G. Rubanovich
The analysis of the modified Wilkinson two-channel cophased power summator-divider (PSD) circuit with a connection of closed stub to the middle point of the ballast resistor (BR) is carried out, that allows compensating resistor parasitic parameters and inproving the characteristics of the device.
The characteristics of the original PSD circuit with lumped BR, with apportioned BR, and modified circuit with adjusting stub were determined using co-phased-antiphased launching method. The equations for exact calculation of its geometric size were estimated. The results of theoretical analysis were confirmed during simulating these variants of devices in Microvawe Office, which affirmed sufficienf improvement of PSD characteristics in case of stub interposition.
For the inicial circuit the parameter of decoupling S12 = -57.3 dB on the central frequency and the bandwidth on the level S12 = -25 dB is ±10%. Transfer cofficients S12, S23 are near -3 dB on the bandwith of ±40%, KU1,2 ≤ 1.1 on the same bandwith, KU3 ≤ 1.25 on the bandwith of ±20%.
The characteristics of circuit with apportined BR were declined so much that impossible to talk about the practical application of the device.
For the circuit with adjusting stub the parameter S12 = -42.7 dB on the central frequency, compared with S12 = -14 dB for the previous case. The Badwith on the level S12 = -25 dB is ±17.5%, that is 1.75 times original. Transfer cofficients S12, S23 = 3.23 dB, that is less than for original circuit by 2.4% but more than for circuit without correction by 8%. Thus, interposition of the adjusting stub led to significant positive results and is recommended for use in engineering practice.
The scope and limitations of examined technical solution were revised, that allow to implement summators in a planar form on substrates made of polycor and ceramics based on BeO for the output level of tens and hundreds watts with acceptable characteristics.