An impedance tuner may include a transmission media for propagating rf signals, a reflection magnitude control device mounted in a fixed position relative to a direction of signal propagation along said transmission media, and a phase shifter to control a reflection phase. A multi-section probe for an impedance tuner system may include a plurality of probe sections and a holder structure for mechanically supporting the plurality of probe sections.
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1. An impedance tuner, comprising:
a transmission media for propagating rf signals;
a reflection magnitude control device mounted in a fixed position relative to a direction of signal propagation along said transmission media; and
a variable phase shifter device to control a reflection phase, said variable phase shifter device mounted in a fixed position relative to said direction of signal propagation.
10. An impedance tuner system, comprising:
a transmission media for propagating rf signals;
a probe system mounted in a fixed position relative to a direction of signal propagation along said transmission media;
a variable phase shifter device to control a reflection phase; and
wherein the probe system includes:
a plurality of probe sections;
a holder structure for mechanically supporting the plurality of probe sections; and
a mechanism to move the plurality of probe sections and the holder structure together in a direction transverse to the direction of signal propagation.
2. The impedance tuner of
3. The tuner of
4. The tuner of
5. The tuner of
6. The impedance tuner of
8. The impedance tuner of
9. The impedance tuner of
11. The tuner system of
0. 12. The tuner system of
a mechanism to move the plurality of probe sections and the holder structure in a direction parallel to the direction of signal propagation.
13. The tuner system of
15. The tuner system of
a transmission media for propagating rf signals;
a probe system mounted in a fixed position relative to a direction of signal propagation along said transmission media;
a variable phase shifter to control a reflection phase; and
wherein the probe system includes:
a plurality of probe sections;
a holder structure for mechanically supporting the plurality of probe sections; and
a mechanism to move the plurality of probe sections and the holder structure in a direction transverse to the direction of signal propagation; and
wherein said plurality of probe sections comprises an even number of spaced probe mismatch sections, and adjacent sections are separated by a gap.
16. The tuner system of
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This application claims the benefit of U.S. Provisional Application No. 60/714,972 filed Sep. 7, 2005, U.S. application Ser. No. 11/468,433, filed Aug. 30, 2006, and is a division of U.S. application Ser. No. 12/555,765, filed Sep. 8, 2009 now U.S Pat. No. 7,808,336, which in turn is a division of U.S. application Ser. No. 11/468,433, filed Aug. 30, 2006, which in turn claims priority from U.S. Provisional Application No. 60/714,972, filed Sep. 7, 2005; the entire contents of each of these applications hereby incorporated by reference.
A slide screw tuner includes a transmission line in some media, such as coaxial, slabline, waveguide, microstrip, etc. One or more probes can move perpendicular to the center conductor. As a probe moves closer to the center conductor, the mismatch at some frequency will increase, while the mismatch decreases as the probe moves away from the center conductor. At some point, when the probe is far enough away, it has very little effect on the fields around the center conductor, so the transmission line looks nearly like a uniform line without a deliberate mismatch.
Features and advantages of the disclosure will readily be appreciated by persons skilled in the art from the following detailed description when read in conjunction with the drawing wherein:
In the following detailed description and in the several figures of the drawing, like elements are identified with like reference numerals. The figures are not to scale, and relative feature sizes may be exaggerated for illustrative purposes.
An aspect of one embodiment provides a technique of controlling phase of the mismatch in a tuner.
The phase shifter may be of any type, although the required mismatch range may put requirements on the maximum loss that can be tolerated. Examples of phase shifters include but are not limited to line stretchers, switched lines, PIN diode phase shifters, varactor diode phase shifters, MEM phase shifters and ferrite phase shifters. Typically, the phase shifter is a variable phase shifter, which may be manually controlled or under an automated control.
This approach to controlling the phase provides flexibility in the design of the reflection magnitude control, since it may be mounted in a fixed location in the transmission line. The reflection magnitude control may be a mechanical probe that moves perpendicular to the transmission media (the center conductor in a TEM line) or it may be a solid state reflection magnitude control, such as a PIN diode or varactor circuit.
An exemplary embodiment of an impedance tuner 50 is schematically illustrated in
Another exemplary embodiment of an impedance tuner 70 is shown schematically in
When a probe such as probe 512 (
In an exemplary embodiment, the probe may have multiple sections. In principle, it can be any number of sections, and, in an exemplary embodiment, designed using filter design techniques to obtain an increased matching range and a specific bandwidth for a particular application.
An exemplary design approach for a multi-section probe is to use an even number of mismatch sections that alternate with gaps. In a gap between any two sections, the transmission line will look nearly like the transmission line without a mismatch probe, and the lengths of the mismatch sections and gaps are selected to give the desired mismatch response vs. frequency. In this exemplary design approach, the impedance of all sections may be variable as the probe is moved perpendicular to the center conductor. All sections may have approximately the same cross section and move together so that for any given position, they are all approximately at the same distance from the center conductor. Therefore, for any given position the characteristic impedance of all sections will be approximately the same. Note that assuming that all the sections are identical is useful for analysis, but not required in practice. Only minor effects are likely to occur due to some deviation due to manufacturing tolerances or the accuracy of the mechanics that move the probe relative to the center conductor.
In an exemplary design approach, a design criteria may be to select a cross section of the probe that gives a good matching range, and to select the lengths of the mismatch sections and gaps. The cross section of the probe may be (although is not limited to) the same as used in single-section probes.
In exemplary embodiments of a design approach, the lengths of the sections and gaps for ideal transmission line sections for probes of different numbers of sections are as follows:
For a 2-section probe, the length of each section and the one gap may all be equal.
In an exemplary embodiment of a design approach, additional sections may be added in pairs with also a pair of gaps, and each time a pair is added, each section length and gap length will be one-half the length of the prior pair of sections. Note that this halving of lengths each time two sections are added is for the ideal transmission line case. In practice, the physical lengths may be adjusted to account for end effects and other physical transmission line effects for the specific transmission media that is used.
Some exemplary embodiments of probe designs for a slab line configuration are shown in
A multi-section probe may be mounted on a carriage as depicted in
This disclosure is not limited to dielectric holders to support multiple probe sections. Dielectric holders may work best when the probes are intended to be non-contacting with the ground slabs. However, if the probes are designed to make direct electrical contact with the ground slabs, then the supporting holder may be made out of any material, including metal, because the electromagnetic fields will not penetrate significantly to the holder area. In this case, any number of sections could even be made out of one piece of metal. One embodiment of this would be to slot the probes from the underside (directly above the center conductor). The slot may be compressed when the probes are inserted in between the slabs, providing spring action side to side against both slabs.
Another approach to the multi-section probe design may use sections which may be either higher or lower impedance than the characteristic impedance of the basic transmission line media. This provides freedom in the tuner design, and more traditional filter approaches may be used.
An exemplary embodiment of an impedance tuner design with transmission line sections that may be either higher or lower impedance than the basic transmission line may use a moving ground plane. Electrically, this is equivalent to moving a probe closer to the center conductor, but in this case, the center conductor is fixed and the ground plane moves.
In the exemplary example of the moving ground plane, multiple sections may be cascaded. At one end of the motion, all sections may be set to the characteristic impedance of the basic transmission line (Z0), so there the reflection magnitude is small. At the other end of the motion, some or all of the sections may be different in impedance, either higher or lower, to create the maximum mismatch. A filter design approach may be used to design the line impedances for the maximum mismatch position. The same design approach could also be used at intermediate positions to control how the overall reflection varies with position.
In
An exemplary embodiment of a tuner using a moving ground plane may be similar to the embodiment of
If a moving ground plane configuration is used, a choke section may be used to help ensure a robust and stable ground plane connection to the fixed ground plane of the main housing, as shown in
Normally, if there is a gap in the ground plane, energy may propagate into and even out through the gap, causing losses and/or sensitivities to the environment outside the ground plane. It may also cause resonances at some frequencies based on the construction geometries. A choke section may comprise a slot cut into the ground plane parallel to the gap to reduce propagation of energy past the slot, reflecting it back out of the gap as if there was a direct connection at that point. A choke section may not reflect all the energy, and may work only over a limited bandwidth, so multiple choke sections may be used to obtain better performance or broader bandwidth.
In a further aspect, a tunable reflection, e.g., a very high reflection magnitude, may be created at a desired frequency. This might typically be at a harmonic frequency, but is not limited to that. If tuning adjustment is included, it will vary the frequency of the high reflection. An exemplary embodiment of this type of reflection control is shown schematically in
Another exemplary embodiment may use a stub 272 with a tunable length, connected to the main transmission line 274, as shown in the system 270 of
An alternate approach is to use a shunt transmission line stub with adjustable length, terminated with a high reflection of arbitrary phase other than an open or a short that can move along the line with a movable connection. The phase may be varied by moving the shunt line along the main transmission line, eliminating the need for a phase shifter in front of the shunt line.
Some transmission line media, such as waveguide, do not have center conductors. In that case, the probe moves into the electromagnetic fields in such a way to cause a mismatch on the transmission line. The concept is the same as for transmission line media with center conductors. Therefore, even though exemplary embodiments described above have employed media with center conductors as examples, the principle is general and applies to all media types.
A schematic diagram of an exemplary embodiment of a tuner system 400 utilizing several of the elements described above is shown in
The operation of the tuner system of
The tuner system 400 of
An exemplary embodiment of applying the tuners described above is for load pull measurements. In general, load pull is any application where a Device Under Test (DUT) will be measured while the impedance presented to it on any DUT port may be varied (“pulled”). This includes both power and noise parameter measurements.
A wide variety of instrumentation is available to include in a load pull system, depending on what aspect of DUT performance is to be measured.
The DUT performance typically depends on the impedances seen by the DUT at the input and output, so the tuners play the important role of creating the desired impedance at each plane.
Among the aspects of embodiments of the disclosure are the following:
Although the foregoing has been a description and illustration of specific embodiments of the invention, various modifications and changes thereto can be made by persons skilled in the art without departing from the scope and spirit of the invention.
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Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Aug 29 2006 | SIMPSON, GARY R | MAURY MICROWAVE, INC | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 045289 | /0139 | |
Apr 12 2014 | Maury Microwave, Inc. | (assignment on the face of the patent) | / | |||
Jun 11 2021 | MAURY MICROWAVE, INC | ABACUS FINANCE GROUP, LLC, AS ADMINISTRATIVE AGENT | SECURITY INTEREST SEE DOCUMENT FOR DETAILS | 056508 | /0424 |
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