Willem
Member level 2
dr oscillator
Hi there
I am designing a 4GHz DRO for my final year thesis.
Up to this point in time i have had minimal success.
I am using a BJt in common base topology as the amplifier. I match the output (collector) of the device for maximum reflection coeffecient. Then I use ADS to examine the input impedance and admittance (at the emmiter) of the device. I then construct a resonator strip (microstrip) to tune the input of the transistor. This strip is then used to couple the "puck" to the circuit. Another important thing is that the strip must be grounded in order to let DC current flow. Now here is the problems and questions:
I am not sure if my method of examining if the oscillation conditions are satsified are correct. What i do is: I do an open loop simulation where I connect term1 to the emitter, and term2 to the resonator strip, all the while having mu output match with a 50ohm load on the collector. I then check if the imaginarry parts of the device input impedance and resonator impedance add to zero. I then close the loop and run a harmonic balance simulation. Is this correct?
If anyone has designed a DRO before and can give me some pointers,I would really appreciate it.
thank you
Willem
Hi there
I am designing a 4GHz DRO for my final year thesis.
Up to this point in time i have had minimal success.
I am using a BJt in common base topology as the amplifier. I match the output (collector) of the device for maximum reflection coeffecient. Then I use ADS to examine the input impedance and admittance (at the emmiter) of the device. I then construct a resonator strip (microstrip) to tune the input of the transistor. This strip is then used to couple the "puck" to the circuit. Another important thing is that the strip must be grounded in order to let DC current flow. Now here is the problems and questions:
I am not sure if my method of examining if the oscillation conditions are satsified are correct. What i do is: I do an open loop simulation where I connect term1 to the emitter, and term2 to the resonator strip, all the while having mu output match with a 50ohm load on the collector. I then check if the imaginarry parts of the device input impedance and resonator impedance add to zero. I then close the loop and run a harmonic balance simulation. Is this correct?
If anyone has designed a DRO before and can give me some pointers,I would really appreciate it.
thank you
Willem