DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION. —The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 7 and 8 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claims 7 and 8 recites “a balanced unbalanced transformer circuit on the radio frequency signal of one of the first frequency and the second frequency and not on the radio frequency signal of the other of the first frequency and the second frequency”. It is nor clear what is meant by the underlined italicized claim limitations. If it is meant that the first balanced unbalanced transformer operates at a first or second frequency while the second balanced unbalanced transformer operates on the other of the first or second frequency (different from the first balanced unbalanced transformer’s operating frequency), then that meaning is not evident from the claim.
For examination purposes on the basis of a prior art, examiner is not clear how to interpret the first and second frequency with respect to the first and second balanced unbalanced transformer, i.e., which one is operating at which of the first and second frequency and which one is operating on other frequency, or if both are operating on the first frequency or both are operating on the second frequency? Unless it is clarified examiner assumed that both are operating at the same frequency.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim 1 is rejected under 35 U.S.C. 102(a)(1) as anticipated by Chung et.al. (“Design of Step-Down Broadband and Low-Loss Ruthroff-Type Baluns Using IPD Technology”, IEEE TRANSACTIONS ON COMPONENTS, PACKAGING AND MANUFACTURING TECHNOLOGY, VOL. 4, NO. 6, JUNE 2014, cited by the applicant).
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Fig. 3(b) of Chung annotated by the examiner for ease of reference.
Regarding claim 1, A balanced-unbalanced transformer circuit (1) comprising:
a main line (2) constituted by a first transmission line having a first end and a second end (designated as EP1 and EP2 respectively by the examiner in the annotated Fig. 3(b) of Chung);
a sub-line (3) coupled to (left col., pp. 969) the main line (2), the sub-line being constituted by a second transmission line having a third end and a fourth end (designated as EP3 and EP4 respectively by the examiner in the annotated Fig. 3(b) of Chung);
an unbalanced node (4) to which an unbalanced signal is input and from which the unbalanced signal is output, the unbalanced node being connected to the first end (EP1);
a first balanced node (5) and a second balanced node (6) to which a balanced signal is input and from which the balanced signal is output; and
a first LC resonant circuit (phase compensation line1, can be considered as a LC resonant circuit, see the footnote) connected between the first balanced node (5) and the unbalanced node (4).
wherein the main line (2) and the sub-line (3) are coupled to each other such that a direction from the first end (EP1) toward (from left to right on the plane of the paper) the second end (EP2) of the main line is identical to a direction from the third end (EP3) toward (from left to right on the plane of the paper) the fourth end (EP4) of the sub-line (see Fig. 3(b) of Chung above),
wherein the first balanced node (5) is connected to the first end (EP1), and the second balanced node (6) is connected to the fourth end (EP4), and
wherein the second end (EP2) and the third end (EP3) are connected to a reference potential (ground).
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 2-6 are rejected under 35 U.S.C. 103 as unpatentable over Chung et al. in view of Gunnarsson et. al. (US 2024/0072405 A1, effectively filed on Jan 21, 2021, before the effective filing date of the current application).
Regarding claims 2-3, Chung teaches all limitations of claim 1, however, the transmission line section of Chung, although can be considered as LC-LC2 resonant may not be analogous to a series LC resonant circuit.
In a similar field of endeavor, Gunnarsson teaches in a balanced-unbalanced transformer, connection of series L-C resonators at different section of the main-line and sub-line of the transformer as claimed. balanced-unbalanced transformers typically possess leakage of high-frequency out-of-band signals between distributed baluns. While resonators (see Fig. 2 of Gunnarsson) for semi-lumped baluns mitigate these deficiencies employing series resonances. Resonator can effectively cancel/short-circuits spurious on the resonant frequencies (Gunnarsson: §0033-§0034).
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Fig. 2 of GUNNARSSON annotated by the examiner for ease of reference.
Therefore, it would have been obvious to a person of ordinary skill in the art to use LC series resonators like Gunnarsson or equivalent parallel L-C tank circuits in place of the phase compensation line as marked in the Chung balanced-unbalanced transformer circuit. So that the benefit of spurious suppression as well as phase compensation can be achieved with a proper lumped LC resonator design where it possible to achieve tunability relatively easy. Further per claims 4, 5 and 6, a pluralities of L-C resonators similar to Gunnarsson can be disposed conveniently between the first balanced node and the first end (similar to 8’ of Gunnarsson), between the second balanced node and the fourth end (similar to 8 of Gunnarsson), or between the first end and the unbalanced node (similar to 8’’), wherein the second LC resonant circuit is disposed where the first LC resonant circuit is not disposed, in order to enable for even higher suppression at higher frequencies.
Claims 7 and 8 are rejected under 35 U.S.C. 103 as unpatentable over Bao et al., (US 2022/0321061 A1, effectively filed on July 11, 2019 earlier than the effective filing date of the current application of November 10, 2022) in view of Chung et al. and further in view of Gunnarsson et. al.
Regarding claims 7 and 8, Bao teaches an amplifier circuit (100b, Fig. 2) comprising:
a first balanced-unbalanced transformer circuit (equivalent to a balanced unbalanced transformer, Bao teaches a power divider, 114) configured to transform a first unbalanced signal (single ended signal Pin into a balanced signal, and to output the balanced signal (differential output to enter into two amplifiers Main 102 and Auxiliary 108 respectively);
a differential amplifier (main and auxiliary amplifier) configured to amplify the balanced signal output from the first balanced-unbalanced transformer circuit; and
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Fig. 2 of Bao et al. annotated by the examiner for ease of reference.
a second balanced-unbalanced transformer circuit (122a) configured to transform the balanced signal output from the differential amplifier (Main 102 and Auxiliary 108) into a second unbalanced signal (output to Pout 124), wherein one of the first balanced-unbalanced transformer circuit (equivalent to a balanced unbalanced transformer, Bao teaches a power divider, 114) and the second balanced-unbalanced transformer (122a) circuit is the balanced-unbalanced transformer circuit according to Claim 1 (Ruthroff transformer 122a is connected between the output 106 of the main amplifier 102 and the output 112 of one of the auxiliary amplifiers 108, §0032), and is configured to operate on a radio frequency signal of a first frequency and a radio frequency signal of a second frequency (The first Ruthroff transformer 122a transfers a low output impedance of the main amplifier to a higher output impedance and thus provides an upward impedance transformation, §0032. Ruthroff transformer can be utilized for both impedance matching and power combining. Ruthroff transformer realizes ideally a 1 :4 impedance transformation based on a transformer with a turns ratio of 1: 1, which has a wide frequency bandwidth, §0024), and
wherein the other, i.e. the the first balanced-unbalanced transformer circuit (in this instance of Bao) is configured to operate as a balanced unbalanced transformer circuit on the radio frequency signal of one of the first frequency and the second frequency and not on the radio frequency signal of the other of the first frequency and the second frequency.
Bao is not explicit about the Ruthroff transformer has an LC resonator as recited in claims 1 and/or 4. However, Chung in view of Gunnarsson teaches LC resonators at different sections of the Ruthroff transformer for spurious rejection and phase transformation as recited in claims 1 and 4.
Therefore, a person of ordinary skill in the art would find it obvious to replace the output balanced unbalanced transformer of Bao with the Chung-Gunnarsson modified form of Ruthroff transformer (recited in claims 1 and 4) for obvious benefits of spurious rejection and phase transformation in order to accomplish better match and combining transformation necessities of the Doherty amplifier of Bao.
Claims 7 and 8 are rejected under 35 U.S.C. 103 as unpatentable over Lin et al., (US 2021/0194451 A1) in view of Chung et al. and further in view of Gunnarsson et. al.
Regarding claims 7 and 8, Lin teaches an amplifier circuit (310, Fig. 7A) comprising:
a first balanced-unbalanced transformer circuit (301) configured to transform a first unbalanced signal (single ended signal Input into a balanced signal, and to output the balanced signal (differential output to enter into two amplifiers 305 and 306 respectively, §0083);
a differential amplifier (305, 306) configured to amplify the balanced signal output from the first balanced-unbalanced transformer circuit; and
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Fig. 7A of Lin et al. annotated by the examiner for ease of reference.
a second balanced-unbalanced transformer circuit (302) configured to transform the balanced signal output from the differential amplifier (305, 306) into a second unbalanced signal (Output), wherein none of the first (301) balanced-unbalanced transformer circuit and the second (302) balanced-unbalanced transformer (122a) circuit is the balanced-unbalanced transformer circuit according to Claims 1 and or claim 4 (i.e. Ruthroff transformer with L-C resonators at different sections) and is configured to operate on a radio frequency signal of a first frequency and a radio frequency signal of a second frequency.
Lin is not explicit about the Ruthroff transformer with an LC resonator as recited in claims 1 and/or 4. However, Chung in view of Gunnarsson teaches LC resonators at different sections of the Ruthroff transformer for spurious rejection and phase transformation as recited in claims 1 and 4.
Therefore, a person of ordinary skill in the art would find it obvious to replace the input or output or both balanced unbalanced transformer of Lin with the Chung-Gunnarsson modified form of Ruthroff transformer (recited in claims 1 and 4) for obvious benefits of broad band operation with spurious rejection and phase transformation in order to accomplish better match and combining transformation necessities of the Push pull amplifier of Lin.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to HAFIZUR RAHMAN whose telephone number is (571)270-0659. The examiner can normally be reached M-F: 10-6.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Andrea Lindgren Baltzell can be reached on (571) 272-1769. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
/HAFIZUR RAHMAN/Primary Examiner, Art Unit 2843.
1 For most lines the effects due to and dominate because of the relatively low series resistance and shunt conductance. The propagation characteristics of the line are described by its loss-free, or lossless, equivalent line, although in practice some information about or is necessary to determine power
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Figure: Transmission line segment: (a) of length; and (b) lumped-element model.
2.2: Transmission Line Theory - Engineering LibreTexts
2 Xiong et al., Development of compact rapid capacitor charging power supply for TMS, IET Power Electronics, IET Power Electron., 2020, Vol. 13 Issue. 12, pp. 2651-2657.