lenght of a 2,4GHz trace
Guest
#3984134
Hi! I would like to build a connection between a integrated bluetoothchip and a chip antenna. I have calculated the thickness of the trace to get the right impedance. But what about the lenght of the trace? In my mind I have the lambda/4 trafo where the lenght is important.. The length of trace is very important for bluetoothchip and antenna integration. I ever managed a project for company (wwww.nod-pcba.com). You can find technical support document on that case section.
Guest
#4042679
orange wrote: > But what about the lenght of the trace? It depends ... Im many cases the length and the impedance of transmission line is used to match the complex impedance of the antenna to the impedance of the transmitter or receiver. Although there are some electronic design programs to do this complex work, it can as well be done manually with a graphic method called the Smith-Chart. But there are a few special cases which can make things easy if they apply: 1. If the impedance of the antenna is real (e.g. 50 Ohm and VSWR approx 1.0) and if it also matches the impedance of the transmission line (microstrip in many cases), then the length of the line does not matter. Of course the longer the line is the higher the attenution will be. 2. If the length of the line is lambda/2 then the impedance at the input and the output oft the T.L. are equal i.e. Zin=Zout. Regardless of the impedance of the T.L. This means that you can either connect the antenna directly to the transmitter or via al lambda/2 line with arbitrary impedance. Reply |