Cavity resonators integrated on MMIC and oscillators incorporating the same
A cavity resonator integrated on a monolithic microwave integrated circuit (MMIC) is provided. The cavity resonator includes a cavity defined by an upper metal surface and a lower metal surface embedded in a low conductivity semiconductor, and a plurality of discrete metal connections coupled between the upper and lower metal surfaces, and at least one port for coupling to the cavity electromagnetically.
1. A semiconductor-based monolithic microwave integrated circuit (MMIC), comprising:
a cavity resonator comprising:
a cavity defined by an upper metal surface and a lower metal surface, the cavity being a low conductivity semiconductor material;
a plurality of discrete metal connections coupled between the upper and lower metal surfaces; and
at least one port for coupling to the cavity electromagnetically, and one or more active devices.
2. The MIMIC of claim 1 in which the plurality of discrete metal connections couple the upper and lower metal surfaces on at least three sides of the cavity.
3. The MMIC of claim 1 in which the cavity is an N-sided polygon.
4. The MIMIC of claim 3 in which the cavity is disposed on a semiconductor substrate having metallization layers and the metal posts connect the metallization layers.
5. The MMIC of claim 1 in which the cavity is circular.
6. The MMIC of claim 1 in which each metal connection of the plurality of discrete metal connections includes a metal post through the semiconductor material.
7. The MMIC of claim 6 in which each metal post includes a backside via.
8. The MMIC of claim 7 in which each backside via is approximately 100 um thick.
9. The MIMIC of claim 1 in which the plurality of metal connections is external to the MMIC and are selected from the group of conductive paste, wire bonds, ribbon bonds, and external packaging.
10. The MMIC of claim 1 further including a ferroelectric material disposed above or below the cavity for tuning a frequency of the cavity.
11. The MMIC of claim 1 in which the at least one port includes a plurality of ports that are coupled together to increase the output current.
12. The MMIC of claim 1 in which the low conductivity semiconductor is selected from the group consisting of gallium arsenide and silicon.
13. An oscillator comprising:
a semiconductor-based monolithic microwave integrated circuit (MIMIC);
a cavity resonator, including:
a cavity defined by an upper metal surface and a lower metal surface, the cavity being a low conductivity semiconductor material,
a plurality of discrete metal connections coupled between the upper and lower metal surfaces; and
a first pair of ports for coupling to the cavity electromagnetically; and
a first amplifier coupled between the first pair of ports of the cavity resonator in a first feedback loop,
wherein the semiconductor-based MMIC includes:
the cavity resonator; and
the first amplifier.
14. The oscillator of claim 13 in which the plurality of discrete metal connections couple the upper and lower metal surfaces on at least three sides of the cavity.
15. The oscillator of claim 13 in which the cavity is an N-sided polygon.
16. The oscillator of claim 13 in which the cavity is circular.
17. The oscillator of claim 13 further including a first phase shifter coupled in the first feedback loop for tuning a frequency of the oscillator.
18. The oscillator of claim 17 further including one or more additional amplifiers coupled in the first feedback loop.
19. The oscillator of claim 13 in which the cavity resonator includes a second pair of ports for coupling to the cavity electromagnetically; and further including a second amplifier coupled between the second pair of ports in a second feedback loop.
20. The oscillator of claim 13 further including a second phase shifter coupled in the second feedback loop for tuning a frequency of the oscillator.