narrow band bridge balun design
I have read some paper,but I don't design the balun！
who can give me some advice?
Which frequency band and how wide ?
Because , balun circuitries are changed by frequency bands and bandwith.
There are three basic ways to do baluns.
1. Transformer types have the widest fractional bandwidth (several octaves) but will not go up to mm wave frequencies.
2. Transmission line types are narrow band but can be used at any frequency. Only their inconvenient size prevents their use at lower frequencies.
3. Lumped element LC bridge types are the narrowest band and the smallest physically.
thank you for all!
for example i want to design a balun with the bandwidth 2-18 G!
may be it is a Marchard Balun,but I have found the dielectric constant
is high,but I only have a dielectric constant equate 2.2 ,thinkness is 0.254mm!for the elaboration,the smallest width for the CPW is 0.1 mm
!how can I do it?
I haven't do it before
Here is an idea that I have never tried to simulate. It might make a good school project.
Split the band in two parts with diplexers. Use two baluns with equal geometric frequency bandwith ratios. Then combine the outputs per phase with diplexers. Your design then would use 2-6 and 6-18 baluns which will be more realizable.
Use single L and single C type diplexers similar to those used in speaker crossovers.
The problem will be the phase and impedance matching of the whole circuit near the crossover frequency.
If this is not very good it might make a masters thesis topic to find out the fundamental limitations and optimum (least defective) design.
here is one paper as a reference.
the bandwidth is not wide, but you can expand easily.
M. Basraui and S.N. Prasad "Wideband, planar, log-periodic balun." 1998 MTT-S
International Microwave Symposium Digest 98.2 (1998 Vol. II [MWSYM]): 785-788
helpful
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It seems to be very useful, but do you have any reference paper to normal (non-log) wideband banluns? Thks in advance
hello
This post seems really interesting.
Log periodic balun looks okay, but how do you expand the bandwidth?
Does anyone have any idea on how to activate this bbalun?
Thanks a lot!
see this:
https://www.edaboard.com/viewtopic.p...6896&highlight