Feedback capacitor
时间：03-23
整理：3721RD
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Hi microwave guys
I'm currently designing microwave oscillators around 4GHz. We tested already one of them and it resonated around 2.2GHz. One reason for the mismatch in frequency can be explained by the fact that we used the wrong Er (3 in stead of 3.5) . But normally i think it doesnt change the freq that much. Or is it?????
The next thing that could change the resonating freq is, as I believe and correct me if I'm wrong: The get the transistor instable i had to add an feedback capacitor from the drain to the ground to make the device instable. But on the final PCB I also had to add extra lines to make it possible to connect drain and gate through te capacitor.
So after testing I wanted to know the influence on the freq of the oscillator of these extra transmission lines. So I made 2 files (see attachement) to simulate the influence of these lines on my S-parameters ( S11) . So first i optimized one part of the design (drawing one)
Procedure: I took into account the extra transmisson lines and and the impedance you need to from the drain. The simulator optimized for a wanted S11 and worked fine. But now I have to do the same for the other side of the oscillator. But here comes the problem that the simulator doesnt find a solution for the S11 I need
So I think I have to simulate the 2 parts forming one schematic and than optimising for S11. But as I need (2 different) S11's on two different places I wanted to know from you if it is possible to do this. ( PS I'm working with APLAC)
Greetz E-goe
I'm currently designing microwave oscillators around 4GHz. We tested already one of them and it resonated around 2.2GHz. One reason for the mismatch in frequency can be explained by the fact that we used the wrong Er (3 in stead of 3.5) . But normally i think it doesnt change the freq that much. Or is it?????
The next thing that could change the resonating freq is, as I believe and correct me if I'm wrong: The get the transistor instable i had to add an feedback capacitor from the drain to the ground to make the device instable. But on the final PCB I also had to add extra lines to make it possible to connect drain and gate through te capacitor.
So after testing I wanted to know the influence on the freq of the oscillator of these extra transmission lines. So I made 2 files (see attachement) to simulate the influence of these lines on my S-parameters ( S11) . So first i optimized one part of the design (drawing one)
Procedure: I took into account the extra transmisson lines and and the impedance you need to from the drain. The simulator optimized for a wanted S11 and worked fine. But now I have to do the same for the other side of the oscillator. But here comes the problem that the simulator doesnt find a solution for the S11 I need
So I think I have to simulate the 2 parts forming one schematic and than optimising for S11. But as I need (2 different) S11's on two different places I wanted to know from you if it is possible to do this. ( PS I'm working with APLAC)
Greetz E-goe