Prosecution Insights
Last updated: April 19, 2026
Application No. 18/858,541

MULTI-TAPERED COAXIAL BALUN

Non-Final OA §102§103
Filed
Oct 21, 2024
Examiner
LOTTER, DAVID E
Art Unit
2845
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
The United States Government (Department of the Navy)
OA Round
1 (Non-Final)
84%
Grant Probability
Favorable
1-2
OA Rounds
2y 3m
To Grant
94%
With Interview

Examiner Intelligence

Grants 84% — above average
84%
Career Allow Rate
493 granted / 584 resolved
+16.4% vs TC avg
Moderate +9% lift
Without
With
+9.4%
Interview Lift
resolved cases with interview
Typical timeline
2y 3m
Avg Prosecution
21 currently pending
Career history
605
Total Applications
across all art units

Statute-Specific Performance

§101
0.3%
-39.7% vs TC avg
§103
49.7%
+9.7% vs TC avg
§102
23.0%
-17.0% vs TC avg
§112
17.8%
-22.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 584 resolved cases

Office Action

§102 §103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Priority Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55. Information Disclosure Statement The information disclosure statements (IDS) submitted on 10/21/2024 and 11/01/2024 are in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner. 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. Claims 1-7 and 9-15 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Kim et al., (KR 10-2005-0006459) - of record, hereinafter Kim. Regarding claim 1 Kim discloses a multi-tapered coaxial balun for use with an antenna, the balun comprising: a coaxial transmission line (e.g., Figs. 1-2, at 201 and 202) including: an inner conductor (e.g., Figs. 1-2 at 201); an outer conductor (e.g., Figs. 1-2 at 202); and a tapered slot (e.g., Figs. 1-2 at 106) provided within the outer conductor, wherein at least one of the inner conductor or the outer conductor is tapered (e.g., Figs. 2 and 3, at 203 and 302; paragraphs 0026-0029). PNG media_image1.png 816 511 media_image1.png Greyscale Regarding claim 2 Kim further discloses the multi-tapered coaxial balun of claim 1, wherein at least one of the inner conductor or the outer conductor is tapered at a respective end of the inner conductor or the outer conductor facing the antenna (e.g., Figs. 2 and 3, at 203 and 302; paragraphs 0026-0028). Regarding claim 3 Kim further discloses the multi-tapered coaxial balun of one of claim 1, further comprising a dielectric material (e.g., Fig. 2, at 202) provided between the inner conductor and the outer conductor. Regarding claim 4 Kim further discloses the multi-tapered coaxial balun of claim 2, wherein both the inner conductor and the outer conductor are tapered (e.g., Figs. 2 and 3, at 201, 203, and 302; paragraphs 0026-0028). Regarding claim 5 Kim further discloses the multi-tapered coaxial balun of claim 4, wherein both the inner conductor and the outer conductor are tapered at respective ends of the inner conductor and the outer conductor facing the antenna (e.g., Figs. 2 and 3, at 201, 203, and 302; paragraphs 0026-0028). Regarding claim 6 Kim further discloses the multi-tapered coaxial balun of claim 1, wherein a slot taper of the tapered slot and respective taper of the at least one of the inner conductor or the outer conductor are configured to produce an impedance matching between an unbalanced end of the coaxial transmission line and the antenna along a length of the balun (e.g., Fig. 1, at 101 and 102; paragraphs 0030-0031). Regarding claim 7 Kim further discloses the multi-tapered coaxial balun of claim 6, wherein the impedance matching is achieved by varying a cross-sectional geometry of at least one of the inner conductor or the outer conductor the length of the balun (e.g., Fig. 1, at 101 and 102; paragraphs 0030-0031). Regarding claim 9 Kim further discloses the multi-tapered coaxial balun of claim 1, wherein the inner conductor has a gradually narrowing conical frustum shape comprising a first radius at a first end of the inner conductor (e.g., Fig. 1, at 101 and 102; paragraphs 0024 and 0030), a second radius at a second end of the inner conductor (e.g., Fig. 1, at 101 and 102; paragraphs 0024 and 0030), and varying radii along a length of the inner conductor, wherein the first radius is larger than the second radius (e.g., Fig. 1, at 101 and 102; paragraphs 0024 and 0030-0031). Regarding claim 10 Kim further discloses the multi-tapered coaxial balun of claim 9, wherein the outer conductor has a gradually narrowing conical frustum shape comprising a third radius at a first end of the outer conductor, a fourth radius at a second end of the outer conductor, and varying radii along a length of the outer conductor, wherein the third radius is larger than the fourth radius (e.g., paragraph 0027). Regarding claim 11 Kim further discloses the multi-tapered coaxial balun of claim 10, wherein the third radius is larger than the first radius (e.g., Figs. 2-3 - visually shown). Regarding claim 12 Kim further discloses the multi-tapered coaxial balun of claim 10, wherein the fourth radius is larger than the second radius (e.g., Figs. 2-3 - visually shown). Regarding claim 13 Kim further discloses the multi-tapered coaxial balun of claim 10, further comprising a feed gap between the second end of the inner conductor and the second end of the outer conductor (e.g., paragraph 0016; Figs. 1-3 - visually shown). Regarding claim 14 Kim further discloses the multi-tapered coaxial balun of claim 1, wherein a first end of the outer conductor comprises a circular arc with an arc dimension equal to a diameter of the outer conductor minus a dimension of the slot (e.g., paragraphs 0009, 0024, 0031; Figs. 1-3 - visually shown). Regarding claim 15 Kim further discloses the multi-tapered coaxial balun of claim 14, wherein a space between the inner conductor and the circular arc is filled with a dielectric material (e.g., paragraph 0016; Figs. 1-3 - visually shown). 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. Claims 8 is rejected under 35 U.S.C. 103 as being unpatentable over Kim. Regarding claim Kim does not explicitly disclose the multi-tapered coaxial balun of claim 6, wherein a balanced-to-unbalanced impedance ratio is greater than 5:1. It would have been obvious to one of ordinary skill in the art before the effective filing date to wherein a balanced-to-unbalanced impedance ratio is greater than 5:1., since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or working ranges involves only routine skill in the art. In re Aller, 105 USPQ 233. Claims 16 is rejected under 35 U.S.C. 103 as being unpatentable over Kim in view of Du Hammel et al., (US 3,013,226) – of record, hereinafter Du Hammel. Regarding claim 16 Kim does not explicitly disclose the multi-tapered coaxial balun of claim 14, wherein a first end of the inner conductor has a first radius and the circular arc of the outer conductor has a second radius with a half angle. Du Hammel discloses wherein a first end of the inner conductor has a first radius and the circular arc of the outer conductor has a second radius with a half angle (e.g., Fig. 2c, at C). It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the multi-tapered coaxial balun disclosed by Kim in accordance with the teaching of Du Hammel regarding wherein a first end of the inner conductor has a first radius and the circular arc of the outer conductor has a second radius with a half angle in order to improve the electrical balance at the output terminals of the balun (Du Hammel, column 2, lines 50-53). PNG media_image2.png 117 339 media_image2.png Greyscale Claims 25-26 are rejected under 35 U.S.C. 103 as being unpatentable over Rahman et al. (US 2017/0338551), hereinafter Rahman, in view of Kim. Regarding claim 25 Tufts discloses an antenna device comprising: an antenna substrate (e.g., Fig. 11, at 1102; paragraph 0091); an antenna (e.g., Fig. 11, at 1101106 an 1108; paragraph 0091); Tufts does not disclose a SubMiniature version A (“SMA”) connector; and a multi-tapered coaxial balun including: an inner conductor; an outer conductor; and a tapered slot provided within the outer conductor, wherein at least one of the inner conductor or the outer conductor is tapered. Kim discloses a SubMiniature version A (“SMA”) connector (Fig. 1, at 104); and a multi-tapered coaxial balun (e.g., Abstract) including: an inner conductor (e.g., Fig. 2, at 201); an outer conductor (e.g., Fig. 2, at 203); and a tapered slot provided within the outer conductor, wherein at least one of the inner conductor or the outer conductor is tapered (e.g., Fig. 2 visually and paragraphs 0026-0028). It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the multi-tapered coaxial balun disclosed by Kim in accordance with the teaching of Kim regarding the use of an SMA connector with multi-tapered coaxial balun in order to reduce the size of the balun (Kim, paragraph 0011). Regarding claim 26 Tufts does not disclose the antenna device of claim 25, wherein the multi-tapered coaxial balun and the SMA connector are printed vertically on a bottom surface of the antenna substrate. Kim discloses wherein the multi-tapered coaxial balun and the SMA connector are printed vertically on a bottom surface of the antenna substrate (e.g., Fig. 1, at 105 and 106). It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the multi-tapered coaxial balun disclosed by Kim in accordance with the teaching of Kim regarding the use of an SMA connector with multi-tapered coaxial balun in order to reduce the size of the balun (Kim, paragraph 0011). Claims 30 and 34 are rejected under 35 U.S.C. 103 as being unpatentable over Rahman in view of Kim in further view of Sherrer et al., (US 2014/0231266), hereinafter Sherrer. Regarding claim 30 Rahman discloses a method for producing an antenna device, the method comprising: printing an antenna on a first surface of an antenna substrate (Fig. 11, at 1106 and 1108); and printing a multi-tapered coaxial balun (Fig. 11, at 1128). Rahman does not disclose a SubMiniature version A (“SMA”) connector on a second surface of the antenna substrate, the second surface of the antenna substrate being opposite the first surface of the antenna substrate; and electrically connecting the multi-tapered coaxial balun and the SMA connector to the antenna, wherein the multi-tapered coaxial balun includes: an inner conductor; an outer conductor; and a tapered slot provided within the outer conductor, wherein at least one of the inner conductor or the outer conductor is tapered. KERI discloses a SubMiniature version A (“SMA”) connector on a second surface of the antenna substrate (e.g., Fig. 1, at 105 and 106), the second surface of the antenna substrate being opposite the first surface of the antenna substrate (e.g., Fig. 1, at 105 and 106); and electrically connecting the multi-tapered coaxial balun and the SMA connector to the antenna, wherein the multi-tapered coaxial balun includes: an inner conductor (e.g., Fig. 2, at 201); an outer conductor (e.g., Fig. 2, at 203); and a tapered slot (e.g., paragraph 0031) provided within the outer conductor, wherein at least one of the inner conductor or the outer conductor is tapered ((e.g., paragraphs 0026-002 0031). It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the multi-tapered coaxial balun disclosed by Kim in accordance with the teaching of Kim regarding the use of an SMA connector with multi-tapered coaxial balun in order to reduce the size of the balun (Kim, paragraph 0011). Rahman as modified does not explicitly disclose a method for producing an antenna device, the method comprising: printing an antenna and printing a coaxial cable on a substrate. Sherrer discloses a method for producing an antenna device, the method comprising: printing a coaxial cable on a substrate (e.g., paragraph 0069) and other mechanical structures (e.g. Abstract). It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the multi-tapered coaxial balun disclosed by Kim in accordance with the teaching of Kim regarding the use of an SMA connector with multi-tapered coaxial balun in order to reduce the size of the balun (Kim, paragraph 0011) and further in accordance of the teachings of Sherrer regarding the method of printing antenna structures in order to provide conductive structures with accuracy to the micron scale (Sherrer, paragraph 0030). Regarding claim 34 Rahman does not disclose the method of claim 30, further comprising selecting an impedance profile that smoothly transitions from an unbalanced input impedance to a balanced load impedance over a length of the balun. Kim discloses selecting an impedance profile that smoothly transitions from an unbalanced input impedance to a balanced load impedance over a length of the balun (e.g., paragraphs 0030-0031). It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the multi-tapered coaxial balun disclosed by Kim in accordance with the teaching of Kim regarding the use of an SMA connector with multi-tapered coaxial balun in order to reduce the size of the balun (Kim, paragraph 0011). Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. The International Search Report disclosed by Applicant contains additional analysis and references considered highly relevant to the current matter. The Examiner has pointed out particular references contained in the prior art of record within the body of this action for the convenience of the Applicant. Although the specified citations are representative of the teachings in the art and are applied to the specific limitations within the individual claim, other passages and figures may apply. Applicant, in preparing the response, should consider fully the entire reference aspotentially teaching all or part of the claimed invention, as well as the context of thepassage as taught by the prior art or disclosed by the Examiner. Any inquiry concerning this communication or earlier communications from the examiner should be directed to DAVID E LOTTER whose telephone number is (571)270-7422. The examiner can normally be reached M-F 10am-6pm. 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, Dameon Levi can be reached at 571-272-2105. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. DAVID E. LOTTER Primary Examiner Art Unit 2845 /DAVID E LOTTER/Primary Examiner, Art Unit 2845
Read full office action

Prosecution Timeline

Oct 21, 2024
Application Filed
Jan 24, 2026
Non-Final Rejection — §102, §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
84%
Grant Probability
94%
With Interview (+9.4%)
2y 3m
Median Time to Grant
Low
PTA Risk
Based on 584 resolved cases by this examiner. Grant probability derived from career allow rate.

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