Prosecution Insights
Last updated: April 19, 2026
Application No. 18/515,035

MULTI-BAND METASURFACE ANTENNA

Non-Final OA §103
Filed
Nov 20, 2023
Examiner
LUONG, HENRY T
Art Unit
2844
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
The University of North Carolina at Charlotte
OA Round
1 (Non-Final)
75%
Grant Probability
Favorable
1-2
OA Rounds
2y 6m
To Grant
95%
With Interview

Examiner Intelligence

Grants 75% — above average
75%
Career Allow Rate
487 granted / 648 resolved
+7.2% vs TC avg
Strong +19% interview lift
Without
With
+19.4%
Interview Lift
resolved cases with interview
Typical timeline
2y 6m
Avg Prosecution
15 currently pending
Career history
663
Total Applications
across all art units

Statute-Specific Performance

§101
1.0%
-39.0% vs TC avg
§103
63.1%
+23.1% vs TC avg
§102
13.9%
-26.1% vs TC avg
§112
14.8%
-25.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 648 resolved cases

Office Action

§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 . Remarks This Office Action is in response to the application filed on 11/20/23. Examiner acknowledged that claims 1-20 are pending. The information disclosure statement (IDS) submitted on 03/21/24 is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner. Drawings The drawings are objected to under 37 CFR 1.83(a). The drawings must show every feature of the invention specified in the claims. Therefore, the plurality of embedded metasurfaces must be shown or the feature(s) canceled from the claim(s) 15. No new matter should be entered. Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance. Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. 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. Claim(s) 1-2, 6, 8-12 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Budhu “The Design of Dual Band Stacked Metasurfaces Using Integral Equations” IEEE Transactions of Antennas and Propagation, Vol., 70, No. 6 June 2022. Regarding Claim 1, Budhu teaches a dual-band metasurface antenna, comprising: a ground layer (Fig. 2: 5); a dielectric layer (Fig. 2: 2, 4) overlying the ground layer; a first metasurface layer (Fig. 2: 1), the first metasurface layer overlying the dielectric layer; and a second metasurface layer (Fig. 2: 3), the second metasurface layer embedded within the dielectric layer. Budhu does not explicitly teach in Fig. 2 a first metasurface layer operates at a first frequency, and a second metasurface layer operates at a second frequency that is higher than the first frequency, wherein at the first frequency of operation, the second metasurface layer presents a high impedance, and at the second frequency of operation, the first metasurface layer presents a high impedance. However, P.1 teaches “where dual band operation is desired, adding additional layers can result in operation at two different frequencies”; p.2 “the design approach is applied to the design of two dual band stacked metasurfaces. The first generates broadside beams at both 2.4GHz and 5.1GHz. The second generates a beam scanned to 30° off broadside when excited”; p4. “frequency-scale the top metasurfaces impedance from ωa to ωb”; Fig. 4 illustrates 2 different impedances ωa to ωb; Fig. 9 and Fig. 10 also illustrates high impedance at different frequency. It would have been obvious to one of ordinary skill in the art before the effective filling of the claimed invention to combine the teachings of Budhu in order to output different impedance using different frequencies. Regarding Claim 2, Budhu teaches the dual-band metasurface antenna of claim 1, wherein: the second frequency is in a range from 200% to 300% the first frequency ([p.2] “first generates broadside beams at both 2.4GHz and 5.1GHz. The second generates a beam scanned to 30° off broadside when excited at 13.4GHz and a broadside beam when excited at 35.75GHz”). Regarding Claim 6, Budhu teaches the dual-band metasurface antenna of claim 1, wherein, each metasurface layer of the first and the second metasurface layers comprises: a plurality of subwavelength unit cells, each unit cell of the plurality of subwavelength unit cells comprising a metallic patch with subwavelength dimensions (Fig. 1). Regarding Claim 8, Budhu teaches the dual-band metasurface antenna of claim 6, wherein, centers of unit cells of the plurality of subwavelength unit cells are arranged at a fixed distance from one another (Fig. 1). Regarding Claim 9, Budhu teaches the dual-band metasurface antenna of claim 6, wherein, a sequence of unit cells of the plurality of subwavelength unit cells includes a periodic pattern provided by modulation of a dimension of respective metallic patches along one direction (Fig. 1). Regarding Claim 10, Budhu teaches the dual-band metasurface antenna of claim 9, wherein, the periodic pattern is configured to provide a radiation behavior of the each metasurface layer at a respective frequency of the first or second frequency (Fig. 9, 10). Regarding Claim 11, Budhu teaches the dual-band metasurface antenna of claim 9, wherein, the periodic pattern is configured to provide a surface impedance of the each metasurface layer at a respective frequency of the first or second frequency, and the surface impedance at the other frequency of the first or second frequency is a high impedance (Fig. 7, 8). Regarding Claim 12, Budhu teaches the dual-band metasurface antenna of claim 9, wherein, the periodic pattern is configured to provide a local periodicity of a surface impedance of the each metasurface layer at a respective frequency of the first or second frequency, and an equivalent impedance of the surface impedance is derived from an equivalent transmission line model based on the local periodicity of the surface impedance (Fig. 7-10). Regarding Claim 14, Budhu teaches the dual-band metasurface antenna of claim 1, wherein, the dielectric layer is provided by bonding a first dielectric slab to a second dielectric slab of equal permittivity, the first metasurface layer overlying the first dielectric slab, and the second metasurface layer overlying the second dielectric slab (Fig. 2). Claim(s) 3 is/are rejected under 35 U.S.C. 103 as being unpatentable over Budhu as applied to claim 1 in view of Borrelli (US 11309635) Regarding Claim 3, Budhu teaches the dual-band metasurface antenna of claim 1 except the first frequency is in a range from 27 GHz to 40 GHz, and the second frequency is in a range from 75 GHz to 110 GHz. Borrelli is in the field of antenna (abstract) and teaches the first frequency is in a range from 27 GHz to 40 GHz, and the second frequency is in a range from 75 GHz to 110 GHz ([Claim 6] “the first waves and the second waves each have a frequency in a range of 20 GHz to 100 GHz”). It would have been obvious to one of ordinary skill in the art before the effective filling of the claimed invention to modify the device of Budhu with the frequencies as taught by Borrelli in order to have frequencies in such ranges since these frequencies are applicable to the 5G infrastructure. Allowable Subject Matter Claim 4-5, 7 and 13 objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. Claim 15-20 are allowable. The following is an examiner’s statement of reasons for allowance: The primary reasons for allowance of the claims 15-20 are due to the inclusion of the following limitations after a comprehensive search of the prior art: "…a plurality of embedded metasurface layers embedded within the dielectric layer, wherein each metasurface layer of the top metasurface layer and the plurality of embedded metasurface layers is configured for operation at a respective frequency of a plurality of different frequencies…" and in combination with the remaining claimed limitations as claimed in the claim(s), i.e., claim 15, (claims 16-18 are allowed as being dependent on claim 15). “…deriving an equivalent first reactance of the first surface impedance from a transmission line model, the equivalent first reactance provided by a first frequency response that includes a pole at zero frequency followed by alternating zeros and poles for increasing frequencies…” and in combination with the remaining claimed limitations as claimed in the claim(s), i.e., claim 19, (claim 20 is allowed as being dependent on claim 19). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to HENRY T LUONG whose telephone number is (571)270-7008. The examiner can normally be reached Monday-Thursday: 8:00-6:00. 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, Regis Betsch can be reached at (571) 270-7101. 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. /Henry Luong/Primary Examiner, Art Unit 2844
Read full office action

Prosecution Timeline

Nov 20, 2023
Application Filed
Feb 25, 2026
Non-Final Rejection — §103
Apr 03, 2026
Interview Requested

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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
75%
Grant Probability
95%
With Interview (+19.4%)
2y 6m
Median Time to Grant
Low
PTA Risk
Based on 648 resolved cases by this examiner. Grant probability derived from career allow rate.

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