| 摘要 |
<p>A stable electromagnetic oscillator (30) comprises an amplifying element (3) in feedback association with a dual mode resonant cavity (12) that provides a double pole bandpass filter function. Two orthogonal modes (1 and 2) of electromagnetic energy resonate within the cavity (12). An output fromthe amplifying element (3) excitationally couples into the first mode (1), while the second mode (2) couples into the input of the amplifying element (3). The output (8) of the oscillator (30) is obtained from the first mode (1). Optional injection lock can be used for greater stability by means of coupling a stable a.c. reference (9) into the cavity (12) in alignment with the second mode (2). Optional electronic frequency tuning comprises a phase or frequency comparator (11) and a reference a.c. source (13), producing a d.c. feedback signal fed to varactor diodes (10). Coupling ports (4, 5, 6, 7) of the cavity (12) can be, e.g., irises, capacitive probes, coaxial probes, or any combination thereof. The electrical field associated with each port (4,5,6,7) is aligned with the electrical field of the mode (1 or 2) coupled thereby. A dielectric resonator can be positioned within the cavity (12) to allow for physical shrinking of the cavity (12) while maintaining the electromagnetic characteristics of the cavity (12).</p> |
