Send your comments to you have a few minutes, you might want to review that time when Mr. Note that you can operate above the Bragg frequency, in theory. At around 60 GHz, there is a dip in S21 and a peak in S11, just as Bragg predicts. The predicted performance is shown below. You could add more dots if you wanted, we were lazy. You could argue that they should be modeled as coupled structures, but for this simple demonstration of Bragg frequency it doesn't really matter. The dots are modelled as tiny capacitances, 10 femto Farads. The Braggs (father and son) are in our humble Microwave Hall of Fame.īelow, we made a crude linear model of Hadrien's chicken-dot T-line. This is where the periodic effects of the chicken dots (or any periodic discontinuity) are spaced 90 degrees apart.
Note that if you looked up even higher in frequency, you would observe a Bragg frequency limitation. (Hadrien says:too lazy to perform a mesh adaptation!)
CHICKEN MATH CALCULATOR TRIAL
Putting chicken dots next to a wirebond will allow you to tune out its inductance by trial and error. You can buy sheets of copper with adhesive backing from DigiKey or even Amazon, it has lots of uses, especially for EMI shielding, and even the "C-word" (crafting). The stick is sharpened to a small square on the end, then a piece of copper is applied to just the tip. The tuning procedure is typically done with a tuning stick (sometimes called a " diddle stick"), made from a sharpened wooden stick such as a high-end cotton swab (not the cardboard ones you clean your ears with. In the ciruit below, there are many dots, but none of them are being used. Unfortunately, there is no practical way to chicken-dot a shorted stub, except perhaps as a way to change its width (and impedance). And you can locate chicken dots on the end of an open circuit stub, to extend its length. You can also think of chicken dots as future open-circuit stubs.
Each dot could add somewhere between 10 and 50 femto-Farads, normally they are disconnected from the circuit and hopefully don't have a major effect on the intended performance more on this later). However, there is still a ton of uncertainty in S-parameters of active circuits, so you should consider ways of tuning a circuit without the expense of a second design iteration.
CHICKEN MATH CALCULATOR SOFTWARE
Maybe we should say "chirp and wire?" The need for chicken dots was much higher before modern EM analysis software made circuit design more accurate, way back in the 1980s. They can be used on soft substrates employing SMT, or chip-and-wire construction.
Can you guess the origin of that name?Ĭhicken dots are used in microstrip circuits, as a means of modifing circuit performance after the circuit is built. The equivalent means of tuning a waveguide structure is known as "dent tuning". It might be a reference to "goose bumps". The origin of the name is not clear, we think it has to do with an engineer being "chicken" that his/her design won't work. and his EM analysis.Ĭhicken dots appears in our microwave slang dictionary.
Thanks to Hadrien for the conversation that started this page. Henrietta lives in Tucson and approves of this page.Ĭlick here to go to our main page on microstripĬlick here to go to our page on microwave slang
0 kommentar(er)
