While musing over a text about transmission line transformers, combiners, splitters and so on, I came up with a power combiner that promises a bandwidth spanning from some kHz well into the GHz domain, with good isolation between input ports, and that does _not_ have a null where its transmission lines are half a wavelength long.
I could find no other examples of this arrangement. The usual combiners are wire- or coax- wound transformers, with 3 decade bandwidths in the 100kHz-100MHz ballpark, or Wilkinson things that only begin to work above half a GHz.
This design should be able to work from a few kHz up to well into the GHz domain. Anyway, for what it's worth, here it is.
Jeroen Belleman
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Version 4 SHEET 1 1044 680 WIRE -432 160 -480 160 WIRE -320 160 -352 160 WIRE -224 160 -240 160 WIRE -112 160 -144 160 WIRE -64 160 -112 160 WIRE 176 160 32 160 WIRE 448 160 176 160 WIRE 688 160 544 160 WIRE -64 192 -112 192 WIRE 112 192 32 192 WIRE 240 192 112 192 WIRE 448 192 400 192 WIRE 592 192 544 192 WIRE 112 240 112 192 WIRE 176 240 176 160 WIRE 688 288 688 160 WIRE 752 288 688 288 WIRE 800 288 752 288 WIRE 896 288 880 288 WIRE -48 368 -96 368 WIRE 112 368 112 320 WIRE 112 368 48 368 WIRE 240 368 400 192 WIRE 240 368 112 368 WIRE 400 368 240 192 WIRE 464 368 400 368 WIRE 592 368 560 368 WIRE -432 400 -480 400 WIRE -320 400 -352 400 WIRE -112 400 -160 400 WIRE -48 400 -112 400 WIRE 176 400 176 320 WIRE 176 400 48 400 WIRE 320 400 176 400 WIRE 464 400 320 400 WIRE 688 400 688 288 WIRE 688 400 560 400 WIRE 320 432 320 400 WIRE 320 544 320 512 FLAG -480 400 0 FLAG -112 192 0 FLAG -480 160 0 FLAG 896 288 0 FLAG -112 400 inb FLAG -112 160 ina FLAG -96 368 0 FLAG 592 368 0 FLAG 592 192 0 FLAG 320 544 0 FLAG 752 288 sum SYMBOL tline 496 176 R0 SYMATTR InstName T2 SYMATTR Value Td=2n Z0=50 SYMBOL tline 512 384 R180 SYMATTR InstName T3 SYMATTR Value Td=2n Z0=50 SYMBOL tline 0 384 R0 SYMATTR InstName T5 SYMATTR Value Td=2n Z0=50 SYMBOL tline -16 176 R0 SYMATTR InstName T6 SYMATTR Value Td=2n Z0=50 SYMBOL res -144 384 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 50 SYMBOL res -128 144 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 50 SYMBOL voltage -224 400 R90 WINDOW 0 -32 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName V1 SYMATTR Value ac 0 SYMBOL voltage -224 160 R90 WINDOW 0 -32 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName V2 SYMATTR Value ac 2 SYMBOL res 160 224 R0 SYMATTR InstName R3 SYMATTR Value 50 SYMBOL res 128 336 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R5 SYMATTR Value 50 SYMBOL res 896 272 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R6 SYMATTR Value 25 SYMBOL bv -336 160 R90 WINDOW 0 -32 56 VBottom 2 WINDOW 3 73 153 VTop 2 SYMATTR InstName B1 SYMATTR Value V=0*exp(-0.5*pow(time/sigma-4,2)) SYMBOL bv -336 400 R90 WINDOW 0 -32 56 VBottom 2 WINDOW 3 73 153 VTop 2 SYMATTR InstName B2 SYMATTR Value V=0.99*exp(-0.5*pow(time/sigma-4,2)) SYMBOL res 336 528 R180 WINDOW 0 36 76 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName R4 SYMATTR Value 1G TEXT -304 584 Left 2 !.ac dec 100 100k 1G TEXT -584 584 Left 2 !.param sigma 500p TEXT -40 584 Left 2 !;tran 20n TEXT -240 56 Left 2 ;Guanella In-phase combiner - Jeroen Belleman, 20251021.