i want to design a Ku-band(working frency about 15GHZ) microstrip antenna .
the first problem is how to chooce the dielect Er(about 2.2 or higher such as 10.2),second is the substrate thickness(i want to use 1.0mm).now,i think useing Er=2.2 and thickness 1.0mm is good. anybody agree with me? if not, i wish experts or my friends to give me advice
best regard
thanks
The higher the er of your PCB, the smaller will your (single!) antenna element be. But also the bandwidth will be lower. If you design an antenna array, the whole antenna won't be smaller even with a high er! So my suggestion use a moderate er of about 3 (2.2 is also OK)
The thickness of the PCB has an influence of the trace-thickness for a 50Ohm trace. the thicker the PCB the thicker the trace. with a 1mm PCB you will get a 50Ohm trace which is more than 1mm thick.... Normally this is not a very good idea, because your 15GHz antenna is also very small (depending on the type of antenna). So I would suggest using a thinner material of about 0.5mm or less. If you must have higher stability of the PCB you can use a 4-layer PCB (which can be thicker)
Take care using a PCB material with a low tand. This is very important for larger antenna arrays. A single antenna will also work fine on a 'bad' material.