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US 4,066,988 AGranted
Electromagnetic resonators having slot-located switches for tuning to different frequencies
AssigneeStanford Research Institute
InventorArthur Karp
Life of this patent
Estimating the term…
Abstract
In a waveguide resonator, either coaxial or noncoaxial, there are inserted spaced slots which establish inductances in series with the waveguide structure at the location of each slot. These slots tune the resonance of the waveguide cavity, which would generally be used in a bandpass filter. Switch means are provided for each slot for discretely altering the value of the inductance established, whereby the resonator or filter may be tuned to a large number of different frequencies.
Claims15
An electronically tunable waveguide resonator comprising:
- walls defining an elongated waveguide resonator,
- each of a plurality of means forming an inductive slot at said walls, said plurality of means being spaced along said walls at predetermined locations, along the axis of said waveguide resonator and each slot being substantially an annular slot about the axis, and
- switch means for selectively shorting each of said plurality of means forming an inductive slot for altering the frequency tuning of said waveguide resonator.
An electronically tunable waveguide resonator comprising:
- walls defining a waveguide resonator,
- each of a plurality of means forming an inductive slot at said walls, said plurality of means being spaced along said walls at predetermined locations along the axis of said waveguide resonator, and
- switch means for selectively shorting each of said plurality of means forming an inductive slot for altering the frequency tuning of said waveguide resonator,
- each of said plurality of means forming an inductive slot comprises a trench cut into the inner surface of said walls, and extending in a direction perpendicular to the axis of said waveguide resonator,
- said switch means comprises a plurality of diode means for each trench, each said plurality of diode means being disposed along a plurality of spaced locations along a trench and bridging the trench of each location, and
- means for biasing each said plurality of diode means to a conductive or non-conductive mode to short the inductance means formed by a trench when the diode means bridging a trench are in the conductive mode.
3 more elements
An electronically tunable waveguide resonator comprising:
- walls defining a waveguide resonator,
- each of a plurality of means forming an inductive slot at said walls, said plurality of means being spaced along said walls at predetermined locations along the axis of said waveguide resonator, and
- switch means for selectively shorting each of said plurality of means forming an inductive slot for altering the frequency tuning of said waveguide resonator,
- each of said plurality of means forming an inductive slot comprises:
- an elongated opening cut through the walls of said waveguide resonator and extending in a direction perpendicular to the axis of said waveguide,
- slot walls extending outwardly from said walls defining said waveguide resonator,
- said slot walls enclosing said elongated opening and defining a trench into which said opening serves as an entrance,
- said switch means comprising a plurality of diode means for each elongated opening disposed over a plurality of locations along the elongated opening and bridging said opening at each location, and
- means for biasing each said plurality of diode means to a conductive or non-conductive mode to short the inductance means formed by said slot walls when the diode means bridging an elongated opening are in the conductive mode.
6 more elements
An electronically tunable coaxial waveguide resonator having an outer cylindrical wall and a hollow central conductor,
- a plurality of trenches formed in the outer periphery of said central conductor, each trench extending at right angles to the axis of said waveguide around said central conductor, said trenches being spaced and positioned at predetermined locations along the length of said central conductor,
- a plurality of diode means for each trench, spaced therealong, and bridging each trench,
- means for selectively biasing each said plurality of diode means to a conductive or a non-conductive mode to short the inductance formed by a trench when in a conductive mode, and
- means for connecting said means for selectively biasing to each of said plurality of diodes through said hollow central conductor.
1 more element
An electronically tunable rectangular-ridged waveguide resonator having rectangular walls defining a rectangular space and a ridge extending into said space from one wall,
- a plurality of trenches formed on the convex surface of said ridge, each trench extending at right angles to the axis of said waveguide, said trenches being spaced at predetermined locations along said ridge length,
- a plurality of diode means for each trench, spaced therealong and bridging each trench, and
- means for selectively biasing each said plurality of diode means to a conductive or non-conductive mode to short the inductance formed by said trench when in the conductive mode.
An electronically tunable waveguide resonator comprising:
- a waveguide resonator having walls defining an elongated cavity and having a central conductor extending through said cavity,
- N trench means forming N inductive slots spaced along said walls, each said trench means forming an inductive slot extending along said walls at right angles to the axis of said waveguide resonator,
- said N trench means being positioned along said waveduide at locations as follows, sin.sup.2 .pi.l.sub.1 /2l = 2sin.sup.2 .pi.l.sub.2 /2l = 4sin.sup.2 .pi.l.sub.3 /2l = . . . = 2.sup.N-1 sin.sup.2 .pi.l.sub.N /2l,
- where each of l.sub.1, l.sub.2, l.sub.3 . . . l.sub.N is a location of a slot measured from a current node of the unloaded waveguide, l is the distance from a current node to a current antinode in the unloaded waveguide, and N is an integer,
- a plurality of diode means for each trench means forming an inductive slot, spaced therealong and bridging each said trench means, and
- means for selectively biasing each said plurality of diode means to a conductive or non-conductive mode to short the inductance formed by said trench means when the plurality of diode means of said trench means are in the conductive mode.
3 more elements
Dependencies are inferred from the claim text.