Pulse generating circuits using drift step recovery devices

A pulse generating circuit comprising:

• a first power supply;
• first and second step recovery transistors having their respective collectors connected to said first power supply;
• first and second series circuits, each comprising a capacitor and a diode, said first and second series circuits connected at one end thereof to the base of said first and second step recovery transistors, respectively, and at the other end thereof to ground, said capacitor in each of said first and second series circuits being prevented from charging by said first power supply when the corresponding one of said first and second step recovery transistors is conducting, said first and second series circuits increasing the duration of time said step recovery diode is conducting and the voltage across said step recovery diode with respect to said first and second step recovery transistors;
• a trigger pulse generating device connected between the base and emitter of each of said first and second step recovery transistors;
• and
• a pulse forming network for receiving power from said first power supply when said trigger pulse is applied to turn on said first and second step recovery transistors, said pulse forming network comprising a storage inductor connected in parallel with a series connected separating diode and a step recovery diode, said separating diode and said step recovery diode being in reverse polarity with respect to each other, a second inductor in series with said storage inductor and connected to the base of said first step recovery transistor, a pumping inductor connected at one end to the base of said second step recovery transistor and at the other end thereof to said step recovery diode, and a load resistor connected to the junction of said step recovery diode and said second inductor;
• wherein current passed via said first and second step recovery transistors increases in said storage inductor, said second inductor and said pumping inductor and is blocked by said separating diode to inject electron-hole plasma from said pumping inductor into said step recovery diode when said first and second step recovery transistors are conducting, said first and second step recovery transistors blocking current at the end of said trigger pulse, said storage inductor and said second inductor reversing polarity to bias said separating diode into a conducting state to extract said plasma from said step recovery diode, said second inductor charging a capacitance corresponding to the collector of said first step recovery transistor and said pumping inductor charging a capacitance corresponding to the collector of said second step recovery transistor, said capacitor in each of said first and second series circuits being charged along with said collector capacitance of said first and second step recovery transistors, respectively, said step recovery diode blocking current after said plasma has been extracted to switch current from said storage inductor and said second inductor into said load resistor to generate a pulse, said second series circuit operating to increase the duration of time said step recovery diode is conducting and the voltage across said step recovery diode with respect to the voltage across said first and second step recovery transistors.

A method of generating a pulse comprising the steps of:

• generating a trigger pulse;
• conducting current through a first step recovery device to supply power to a pulse forming network for substantially the duration of said trigger pulse;
• providing power to a pumping inductor and a storage inductor in said pulse forming network with current;
• preventing current from flowing from said storage inductor to a second step recovery device in said pulse forming network during said conducting step;
• injecting electron-hole plasma into said second step recovery device from said pumping inductor during said conducting step;
• supplying current from said storage inductor to said second step recovery device after said conducting step to extract plasma from said second step recovery device until substantially all plasma is extracted from said second step recovery device;
• and
• switching current of said storage inductor from said second step recovery device to a load resistance to generate a pulse;
• wherein said first step recovery device is a step recovery transistor and further comprising the step of decreasing recharging of the capacitance associated with the transistor collector into said load resistance, said decreasing step comprising the steps of:
• providing power to a second inductor during said conducting step;
• charging said collector capacitance via said second inductor during said preventing step;
• adding current from said second inductor to current from said storage inductor to extract plasma during said supplying step;
• and
• switching current of said second inductor to said load resistance during said switching step for switching current of said storage inductor from said second step recovery device to a load resistance to generate said pulse.

A method of generating a pulse comprising the steps of:

• generating a trigger pulse;
• conducting current through a first step recovery device to supply power to a pulse forming network for substantially the duration of said trigger pulse;
• providing power to a pumping inductor and a storage inductor in said pulse forming network with current;
• preventing current from flowing from said storage inductor to a second step recovery device in said pulse forming network during said conducting step;
• injecting electron-hole plasma into said second step recovery device from said pumping inductor during said conducting step;
• supplying current from said storage inductor to said second step recovery device after said conducting step to extract plasma from said second step recovery device until substantially all plasma is extracted from said second step recovery device;
• and
• switching current of said storage inductor from said second step recovery device to a load resistance to generate a pulse;
• wherein said first step recovery device is a step recovery transistor and further comprising the step of connecting a first diode and a first capacitor in parallel with the capacitance associated with the collector of said step recovery transistor to increase voltage across said second step recovery device with respect to said step recovery transistor and the duration of time said second step recovery device conducts current during said supplying step.

A method of generating a pulse comprising the steps of:

• generating a trigger pulse;
• conducting current through a first step recovery device to supply power to a pulse forming network for substantially the duration of said trigger pulse;
• providing power to a pumping inductor and a storage inductor in said pulse forming network with current;
• preventing current from flowing from said storage inductor to a second step recovery device in said pulse forming network during said conducting step;
• injecting electron-hole plasma into said second step recovery device from said pumping inductor during said conducting step;
• supplying current from said storage inductor to said second step recovery device after said conducting step to extract plasma from said second step recovery device until substantially all plasma is extracted from said second step recovery device;
• and
• switching current of said storage inductor from said second step recovery device to a load resistance to generate a pulse;
• wherein said pulse forming network further comprises a first step recovery transistor connected to said pumping inductor, and further comprising the step of increasing current in said pumping inductor by conducting current through said first step recovery transistor.