Litigation

Maxell Ltd. v. ZTE Corp.

settled

5:18-cv-00080

Patents at issue (1)

6816491

Plaintiffs (1)

Defendants (1)

Summary

A related action against ZTE Corp. was bifurcated into this E.D. Tex. case and settled on the same terms as the principal ZTE matter.

Case overview & background

Plain-language overview of the case: parties, accused product, patents at issue, and why the suit matters.

I'll research this case before drafting.

Let me verify the '491 patent's title and the IPR history, plus the docket details.

Case Overview: Maxell Ltd. v. ZTE Corp., No. 5:18-cv-00080 (E.D. Tex.)

The parties. Maxell, Ltd. is a Japanese consumer-electronics and energy/storage-products manufacturer — the successor to Hitachi Maxell, which received the asserted patents through Hitachi's consumer-electronics reorganization (Hitachi → Hitachi Consumer Electronics → Hitachi Maxell → Maxell). Maxell itself does not make smartphones; its mobile-device portfolio is monetized through a licensing program backed by litigation, so although it is an operating company (not a classic NPE/PAE), its assertion campaign against handset makers has been analyzed in the NPE-assertion literature. The defendant here is ZTE Corporation, the Shenzhen-based telecommunications-equipment and smartphone manufacturer, sued separately from its U.S. subsidiary ZTE (USA) Inc. (Richardson, Tex.), which had already gone to judgment in the companion case, Maxell Ltd. v. ZTE Corp. et al., No. 5:16-cv-00179-RWS (E.D. Tex.). Note that the metadata for this matter lists only U.S. Patent No. 6,816,491; the severed ZTE Corp. action arose out of the same November 18, 2016 complaint and, per contemporaneous reporting, carried the same seven-patent set that went to verdict — but I could not locate a docket entry in 5:18-cv-00080 confirming the precise patent list, so treat that point as reported rather than docket-verified. (Law360 via Mayer Brown; Docketbird)

The technology and the patent. The '491 patent, titled "Multiplexed audio data decoding apparatus and receiver apparatus," claims a packet-based audio decoder architecture in which multiple decoding program codes are stored in an external ROM and transferred into an internal RAM when the compression/encoding format of a selected multiplexed audio stream changes, with a DSP then decoding using the loaded code. The point of the invention is flexibility and reduced on-chip ROM: a handset can support new codecs (e.g., MP3, AAC variants) without silicon redesign. In the companion case, the jury found claims 1 and 8 of the '491 patent infringed by ZTE smartphones including the ZMax 2 and Axon 7, and the court construed the '491 terms (including the disputed "demultiplexer" limitation and means-plus-function treatment of the "receiving means" and preamble terms) in Maxell Ltd. v. Huawei Device U.S. Inc., 297 F. Supp. 3d 668 (E.D. Tex. 2018). (CourtListener opinion; RPX litigation document with accused-product list)

Procedural posture and venue. The parent suit was filed November 18, 2016 in the Texarkana Division of the Eastern District of Texas before Judge Robert W. Schroeder III. ZTE Corp. refused service, which stalled the case for nearly a year until Judge Schroeder bifurcated the ZTE USA and ZTE Corp. claims in March 2018, sending the ZTE USA claims to a two-week jury trial that began June 18, 2018. On June 29, 2018, the jury found willful infringement of all seven asserted patents and awarded $43.3 million. This case, No. 5:18-cv-00080, was docketed June 15, 2018 as the vehicle for the severed ZTE Corp. claims; on February 4, 2019, the parties filed an identical joint motion to stay and notice of settlement in both cases, telling Judge Schroeder that "all matters in controversy between the parties have been settled in principle," with the agreement filed under seal. (Docketbird lists the cause of action as 15 U.S.C. § 1126, which appears to be a docketing artifact — the case is a 35 U.S.C. § 271 patent action.) Venue mattered because ZTE (USA) maintained its principal U.S. office in Richardson, Texas and a call center in Plano, both inside the district, and because the district's Texarkana docket before Judge Schroeder was handling the parallel Huawei case — but note the pre-TC Heartland filing date and ZTE's actual Texas presence mean this case was not a pure "hot tub" venue play. (Law360 verdict coverage; RPX/venue allegations from the 2018 complaint)

Why it is notable. Three things. First, the IPR linkage: ZTE filed a coordinated wave of PTAB petitions against the asserted patents (e.g., IPR2018-00235 on the '317 patent, IPR2018-00236 on the '493 patent, both denied institution June 1, 2018), and the Board denied institution on all seven — the last denial landing July 2, 2018, three days after the verdict. Maxell used those denials offensively, filing a request for judicial notice of them in the district court and citing the "verdict on seven patents … each of these asserted patents also survived IPR petitions filed by ZTE" in a subsequent licensing demand letter to Apple dated October 9, 2018. That sequence — trial verdict plus a clean PTAB sweep — is an unusually strong patent-owner outcome and a frequently cited example of IPR petitions failing to derail a fast EDTX case. Second, the damages/market context: $43.3M with a willfulness finding exposed ZTE to trebling under § 284, and the verdict came while ZTE was under U.S. export-restriction pressure in mid-2018, which likely shaped its incentive to settle confidentially rather than litigate the ZTE Corp. claims and post-trial motions (including the jury's unusual "routine and conventional" Alice-related finding). Third, the assertion pattern: the '491 patent and its siblings were redeployed in Maxell Ltd. v. Apple Inc., No. 5:19-cv-00036-RWS (E.D. Tex.) and against other handset makers, making the ZTE outcome the template for Maxell's broader smartphone-licensing campaign.

Sourcing caveats: the $43.3M verdict, bifurcation, trial dates, settlement timing, and counsel are well documented in Law360/WIPR reporting and reproduced on Mayer Brown's site. The specific docket entry numbers for the verdict, the bifurcation order, and the dismissal in 5:18-cv-00080 are not confirmed here; I did not retrieve the 5:18-cv-00080 docket sheet, so the dismissal date and the exact patent list carried into that severed case should be verified on PACER or RPX before being stated as docket fact.

Key legal developments & outcome

Major rulings, motions, claim construction, settlements, and the present posture or final disposition.

I'll research this case systematically, starting with the docket and patent.

Rich initial results. Let me dig into the specific docket and the PTAB proceedings.

Now let me pull the actual docket for 5:18-cv-00080 and the PTAB petition list.

Case Posture Summary — Maxell Ltd. v. ZTE Corp., No. 5:18-cv-00080-RWS (E.D. Tex., Texarkana Div.)

Bottom line: No. 5:18-cv-00080 is the severed/bifurcated end of Maxell's 2016 ZTE campaign — the vehicle that carried the claims against the Chinese parent, ZTE Corp., after Judge Robert W. Schroeder III split the parent from U.S. subsidiary ZTE (USA) Inc. The substantive merits — including the validity, construction, and infringement of U.S. Patent No. 6,816,491 (the '491 patent, "Multiplexed audio data decoding apparatus and receiver apparatus") — were litigated and tried in the companion case, No. 5:16-cv-00179-RWS, where a Texarkana jury returned a $43.3 million willfulness verdict on 2018‑06‑29. That verdict was never reduced to judgment; the parties settled confidentially in February–March 2019, and the '491 claims in No. 5:18-cv-00080 were resolved on identical terms.

1. Filing & initial pleadings

Date Event
2016‑11‑18 Maxell, Ltd. sues Huawei (No. 5:16-cv-00178-RWS) and ZTE Corp. + ZTE (USA) Inc. (No. 5:16-cv-00179-RWS

In the news

What the press has reported about this case, summarized with links to the source articles.

I'll start by researching this case across multiple search angles.

Now let me dig into coverage of the settlement and the specific patent.

Let me search additional angles — PTAB/IPR coverage, IPWatchdog/Patently-O commentary, and mainstream/analyst reaction.

Press coverage of Maxell Ltd. v. ZTE Corp., No. 5:18-cv-00080 (E.D. Tex.)

One threshold finding: no outlet appears to have written a story about No. 5:18-cv-00080 as such. The case — the March 2018 bifurcation of Maxell's original November 2016 ZTE suit, docketed separately because ZTE Corp. (Shenzhen) would not accept service — appears in the press almost entirely as a tag-along to its parent case, No. 5:16-cv-00179, where the substantive rulings happened. Every article below discusses the ZTE dispute as a whole and cites 5:18-cv-00080 only as the companion/bifurcated suit.

The verdict. Law360 (Dorothy Atkins, 2018-07-02) reported that a six-member Texarkana jury found on Friday, June 29, 2018 that ZTE USA Inc. willfully infringed seven Maxell smartphone patents and awarded $43.3 million, with willfulness exposing ZTE to treble damages; the article identifies 5:18-cv-00080 as "the bifurcated suit" and notes the claims against ZTE Corp. remained pending there. Law.com (2018-07-02) added detail that the jury gave Maxell "its entire ask of a $43 million reasonable royalty," that at least some of the patents touched 105 accused ZTE products, that Maxell holds a 5,300-patent portfolio largely bought from Hitachi's optronics division in 2013, and — per RPX data it cited — that Maxell was then litigating roughly 47 patents against BlackBerry, Olympus, Huawei, ASUSTeK, Blu, Fandango and FOTV. WIPR, republished by China IP Lawyer (2018-07-04) framed it as ZTE and ZTE USA being "ordered to pay" $43.3 million over seven patents. On the specific patent in this case — U.S. Patent No. 6,816,491, a multiplexed audio-data decoding/receiving patent — Chinese trade outlet 知产力 (China IP Lawyer) (2018-07-05) published the only detailed verdict table I could find, reporting the jury found claims 1 and 8 of the '491 patent willfully infringed by the ZMax 2 and Axon 7 handsets.

Significance as framed by the press. Outlets treated the case less as a doctrinal milestone than as a portfolio-monetization event and a defensive-loss datapoint for a Chinese handset maker already under US government pressure. Law.com reported that the Patent Trial and Appeal Board on Monday, July 2, 2018 turned away the last of ZTE's seven administrative validity challenges to the patents — a point Maxell's own counsel later pressed in licensing correspondence. Law360 flagged a wrinkle the court record alone would not surface: the jury also found some claims "routine and conventional" for purposes of Alice step two, and Maxell's Jamie Beaber said he had never seen that question put to a jury and that Maxell had objected to it, leaving the § 101 issue for post-trial motions. Both Law360 and WIPR quoted Beaber's reaction — "the jury got this one right" / "the jury absolutely got this one correct" — which is advocacy, not record. Law.com also went beyond the docket with an executive-side detail: Beaber said ZTE had worried about publicity from the Trump administration's fight with ZTE, but voir dire showed only two of 42 prospective jurors knew of it.

The settlement. Law360 (Daniel Siegal, 2019-02-04) reported a confidential settlement, quoting the parties' joint motion telling Judge Robert W. Schroeder III that "All matters in controversy between the parties have been settled in principle," with the deal to be filed under seal and deadlines stayed 30 days. Critically for this case number, the article states that "Maxell and ZTE Corp. filed an identical notice of settlement in the bifurcated case as well" — i.e., No. 5:18-cv-00080 settled on the same terms. No outlet reported a dollar figure for the settlement; Law360 said a ZTE attorney declined comment and Maxell's counsel did not respond. Law360 (2019-02-21) later placed the ZTE deal in context when Maxell settled with Huawei: "The Huawei settlement comes weeks after Maxell settled another patent suit, this one with Chinese smartphone maker ZTE USA Inc."

Where accounts diverge. (1) Timing: Law360 reported a settlement in principle in early February 2019, whereas ZTE's 2018 Annual Report states that "In March 2019, the Company and ZTE USA reached a settlement with Maxell, and the Eastern District of Texas … approved the request for withdrawal" — a company-side characterization that compresses the February notice into a March consummation. ZTE's report also told investors the cases "will not have any material adverse impact on the financial conditions and operating results of the Group," an issuer statement no court filing confirms. (2) Patent subject matter: Law360 describes camera, cellular-data, power-supply, audio-decoding and walking-navigation patents, while WIPR says the eight patents "relate to wireless flash drives, multimedia devices, and storage and memory devices" — a materially different gloss on the same list. (3) The '443 patent: Law360 says ZTE voluntarily withdrew the expired '443 patent before trial; WIPR says the jury "did not give a ruling on the '443 patent," which reads as an adjudicated non-finding rather than a withdrawal. (4) A practitioner piece by Maxell's own counsel, Kfir Levy, "Smartphone battle reveals breadth of 'phone' tech," Intellectual Property Magazine (Oct. 2018, pp. 52–53), appears to analyze the verdict — but I could only locate a bibliographic record of it, not the text, so I cannot characterize its arguments.

Coverage gaps. I found no Reuters, Bloomberg Law, Ars Technica, The Verge, IPWatchdog, Patently-O, JD Supra or EFF Deeplinks article on this dispute. The reporting is confined to legal trade press (Law360, Law.com/ALM, WIPR) plus Chinese-language IP trade outlets, and all of it centers on the 2018 trial and the 2019 settlement rather than on No. 5:18-cv-00080 individually; the settlement amount, the license terms, and the disposition of the Alice issue flagged at verdict were never publicly reported.

Sources

Plaintiff representatives

Counsel of record for the plaintiff(s): attorneys, firms, and roles (lead counsel, of counsel, local counsel).

I'll research the counsel of record for Maxell Ltd. in this case.

Counsel of Record for Plaintiff Maxell, Ltd. — Maxell Ltd. v. ZTE Corp., No. 5:18-cv-00080-RWS (E.D. Tex.)

Sourcing note up front

This case is the bifurcated companion to Maxell, Ltd. v. ZTE Corp. et al., No. 5:16-cv-00179-RWS. Because ZTE Corp. (the Shenzhen parent) never accepted service or answered, and the case ended in a confidential settlement notice filed February 4, 2019 (the same day as the identical notice in the parent case), there was almost no contested motion practice in 5:18-cv-00080 itself. The plaintiff's roster below is drawn from (a) the attorney list on the Justia docket for 5:18-cv-00080, (b) signature blocks on Maxell's filings in the companion cases, and (c) the trial appearance list from the June 2018 ZTE trial. PACER was not directly accessible to me, so I could not verify each individual notice of appearance by docket-entry number in 5:18-cv-00080; no sealing issue affects the roster (counsel lists are public), but individual appearance dates are unverified.

Lead counsel — Mayer Brown LLP

Attorney Role Firm / Office Note
Jamie B. Beaber Lead counsel (confirmed: Maxell's own PTAB filing states "Mr. Beaber is lead counsel for the plaintiff… in Maxell, Ltd. v. ZTE Corporation, et al., Case No. 5:16-cv-00179-RWS") Mayer Brown LLP, 1999 K Street NW, Washington, DC First-chair in the ZTE trial; spokesperson for Maxell to Law360 after the $43.3M verdict; member of D.C. and Michigan bars, admitted to the Federal Circuit and E.D. Tex.; substantial ITC and district-court patent practice.
Alan M. Grimaldi Senior trial counsel / co-lead Mayer Brown LLP, Washington, DC Mayer Brown partner; his firm bio credits him as "[p]art of the trial team that secured a $43.3m verdict" in Maxell v. ZTE and lists Maxell campaigns against Apple, Vizio, Lenovo and BLU; Chambers USA and IAM Patent 1000 honoree.

Trial team / of counsel — Mayer Brown LLP (Washington, DC unless noted)

Attorney Role Office Note
Kfir B. Levy Trial team Washington, DC Appeared at the ZTE trial; part of the Maxell core team in the related Apple and Huawei matters.
James A. ("Tripp") Fussell III Trial team Washington, DC Appeared at the ZTE trial; Maxell trial team in related suits.
William J. ("Justin") Barrow Trial team Washington, DC Appeared at the ZTE trial; listed on Maxell's later filings in the Apple case.
Tiffany A. Miller Trial team Washington, DC Appeared at the ZTE trial; handled discovery/exhibit-list correspondence with ZTE's Pillsbury counsel.
Baldine B. Paul Trial team Washington, DC Appeared at the ZTE trial.
Saqib J. Siddiqui Trial team Washington, DC Appeared at the ZTE trial; listed on Maxell's Apple-case filings.
Bryan C. Nese Trial team Washington, DC Appeared at the ZTE trial; Law360's Feb. 2019 settlement story identifies him as Maxell counsel.
Clark S. Bakewell Trial team; declaration/fact witness support Washington, DC (Maryland bar) Executed the Aug. 3, 2018 declaration supporting Maxell's post-trial and renewed JMOL motions in the companion case, stating "I represent Plaintiff Maxell, Ltd."; admitted pro hac vice in E.D. Tex.
Alison T. Gelsleichter Trial team Washington, DC Named in the E.D. Tex. counsel listing and on Maxell's Apple-case signature blocks.
Justin Park Associate/attorney (during this case) Washington, DC On the 5:18-cv-00080 docket list. Notably, he later moved to DLA Piper, which became the subject of Maxell's 2020 motion to disqualify DLA Piper in Maxell v. Apple (5:19-cv-00036) based on his possession of Maxell confidential information from the Maxell smartphone matters.
Tyler J. Earnest Attorney Washington, DC Listed in the consolidated E.D. Tex. counsel roster for the Maxell–ZTE litigation; on the 5:18-cv-00080 docket list.
Michael T. / Michael L. Lindinger Attorney Washington, DC On the 5:18-cv-00080 docket list and Maxell signature blocks (first name appears both as "Michael T." and "Michael L." in public sources).
Robert G. Pluta Of counsel / IPR lead Mayer Brown LLP, 71 S. Wacker Drive, Chicago, IL Registered patent attorney (Reg. No. 50,970); lead counsel for Maxell before the PTAB in the ZTE IPRs (e.g., IPR2018-00235 on the '317 patent), with Beaber as back-up counsel.
Amanda Streff Bonner Attorney Chicago, IL Listed in the consolidated E.D. Tex. counsel roster and on Maxell signature blocks in the related cases.

Local counsel — Patton, Tidwell & Culbertson, LLP (Texarkana)

Attorney Role Firm / Office Note
Geoffrey Patton Culbertson Local counsel (E.D. Tex.) Patton, Tidwell & Culbertson, LLP, 2800 Texas Blvd., Texarkana, TX 75503 Signed the February 4, 2019 joint motion to stay/notice of settlement on behalf of Maxell; appeared at the ZTE trial as the only non-Mayer Brown member of Maxell's trial team; the firm appears in older filings as "Patton Tidwell & Schroeder, LLP."
Kelly Tidwell Partner at the local firm; likely involved, not confirmed as appearing in 5:18-cv-00080 Same firm Named in the firm name and on Maxell signature blocks in the later Apple case; I could not confirm a notice of appearance by him in this docket.

In-house counsel

I found no Maxell in-house attorney appearing as counsel of record on this docket, and no publicly identified Maxell in-house lawyer for this matter. Maxell's licensing/IP-transaction function handled parallel negotiations (referenced in Beaber's October 9, 2018 letter to Apple), but no name is established for this case — I will not guess.

Cautions / open items

  1. "Lead counsel" is not a docket designation here. It is established by Maxell's own PTAB pro hac vice motion (Beaber as lead counsel in the ZTE litigation) and by his role as trial first chair and press spokesperson. Roles for the rest of the team are inferred from appearance lists and signature blocks, not formal docket labels

Defendant representatives

Counsel of record for the defendant(s): attorneys, firms, and roles (lead counsel, of counsel, local counsel).

Bottom line first

No attorney appears to have entered an appearance for ZTE Corporation in 5:18-cv-00080. The publicly available docket data for that severed case lists counsel only for the plaintiff. This is consistent with the case's unusual procedural history: ZTE Corp. (the Shenzhen parent) never accepted service in the parent action, the Court bifurcated the ZTE USA and ZTE Corp. claims in March 2018, and the ZTE Corp. claims were carried in this separate cause number, which was resolved by the February/March 2019 confidential settlement before ZTE Corp. ever litigated on the merits.

Caveat: I could not pull the PACER docket sheet itself (paywalled) or a RECAP mirror for 5:18-cv-00080. If ZTE Corp. filed a notice of appearance, an unopposed motion for extension, or a pro hac vice application in that cause number, it would show only on PACER. Treat the "no counsel of record" conclusion as strongly supported but not PACER-verified.

The ZTE-side team that actually ran this patent family

Because 5:18-cv-00080 is a carve-out of the same asserted patents as the parent case (including U.S. Patent No. 6,816,491, the '491 patent identified in your metadata), the attorneys doing ZTE's work on this patent family — and the ones who would have been positioned to appear for ZTE Corp. — are the following.

Pillsbury Winthrop Shaw Pittman LLP — ZTE's trial counsel (parent case 5:16-cv-00179)

Name Role Office Note
Steven A. Moore Lead counsel for ZTE (USA) Inc. Pillsbury, Washington, D.C. (firm-wide IP litigation leadership) Listed first among ZTE's counsel in Law360's July 2018 verdict coverage; a long-standing ZTE defense lawyer in E.D. Tex. cellular cases (e.g., Cellular Communications Equipment v. ZTE/HTC).
Nicole S. Cunningham ZTE (USA) counsel of record; signed the P.R. 4-5(d) joint claim construction chart as "Counsel for Defendant ZTE (USA) INC." Pillsbury, San Diego, CA Texas bar No. 234390 per her signature block; day-to-day E.D. Tex. discovery/claim construction point person.
Sara J. O'Connell ZTE (USA) counsel of record; filed the sealed post-trial declaration (Dkt. 291) opposing Maxell's renewed JMOL Pillsbury, 501 W. Broadway, Ste. 1100, San Diego, CA Post-trial/ JMOL opposition work in the ZTE USA case.
Callie A. Bjurstrom ZTE (USA) counsel Pillsbury (San Diego/DC) Named in Law360's trial-team list; patent litigation associate/partner on the ZTE account.
Matthew R. Stephens ZTE (USA) counsel Pillsbury Named in Law360's trial-team list; also signed ZTE (USA)'s claim construction papers.
Rene E. Mai Earlier ZTE notice of appearance (related E.D. Tex. ZTE matters, e.g., 6:13-cv-507) Pillsbury, 501 W. Broadway, Ste. 1100, San Diego, CA Predecessor San Diego ZTE relationship partner; co-counsel with O'Connell/Cunningham.

Sources: Law360 verdict coverage (July 2, 2018) and settlement coverage (Feb. 4, 2019), reproduced at the Mayer Brown link above; the P.R. 4-5(d) Joint Claim Construction Chart in 5:16-cv-00179 (Nov. 3, 2017); Dkt. 291/292 filings in 5:16-cv-00179.

Finnegan, Henderson, Farabow, Garrett & Dunner LLP — ZTE's later/post-trial and PTAB counsel

Name Role Office Note
Lionel M. Lavenue Counsel for ZTE USA as reported at the time of the February 2019 settlement (i.e., post-trial/JMOL and appeal posture) Finnegan, Washington, D.C. Prominent PTAB practitioner; Finnegan filed the ZTE-side IPR petitions against Maxell (IPR2018-00235/-00236/-00237/-00238, filed Nov. 22, 2017, naming ZTE Corporation as real party in interest).

Sources: Law360 settlement story ("ZTE USA is represented by Lionel M. Lavenue of Finnegan Henderson Farabow Garrett & Dunner LLP"); PTAB related-matter statements identifying ZTE Corporation et al. v. Maxell, Ltd., IPR2018-00236 (filed Nov. 22, 2017).

Unsourced / do not rely on: I could not retrieve the IPR petitions' counsel signature blocks to confirm Finnegan's lead/back-up counsel designation for ZTE, nor a Finnegan pro hac vice appearance in 5:18-cv-00080 or 5:16-cv-00179. The inference that Finnegan served as ZTE Corp.'s counsel for the severed case is circumstantial only. Likewise, I found no evidence of separate local counsel for ZTE in the Texarkana cases — Pillsbury appears to have appeared directly, which is common where a party has no local-counsel requirement under the E.D. Tex. local rules.

In-house

No ZTE in-house counsel is identified by name in any public filing I could locate. ZTE Corp.'s annual report refers only generically to "the attorney appointed by ZTE USA."

For contrast: plaintiff's side in 5:18-cv-00080

Maxell was represented by Mayer Brown LLP — Jamie B. Beaber, Alan M. Grimaldi, Kfir B. Levy, James A. "Tripp" Fussell III, Robert G. Pluta, Baldine B. Paul, Saqib J. Siddiqui, Tiffany A. Miller, William J. Barrow, Amanda S. Bonner, Brian C. Nese, Clark S. Bakewell — with Patton Tidwell & Culbertson LLP (Geoffrey P. Culbertson, Kelly Tidwell) as local counsel out of Longview/Texarkana, and later Findlay Craft P.C. (Alison T. Gelsleichter, Tyler, TX) appearing in the 5:18-cv-00080 docket per Justia. This asymmetry — a fully briefed plaintiff's appearance block and an empty defendant block — is the strongest docket-level signal that ZTE Corp. defaulted to non-appearance in this severed case.

Research gaps you should close before publication

  1. PACER docket for 5:18-cv-00080 — check the "Attorneys" tab and any entries between Dkt. 1 (6/15/2018) and the March 2019 dismissal. Look specifically for a Rule 12 motion, waiver of service, or stipulation of dismissal that might bear a ZTE Corp. signature block.
  2. The Feb. 2019 joint notice of settlement in 5:18-cv-00080 — its signature block would reveal whether anyone signed for ZTE Corp. even absent a formal appearance.
  3. Stipulation of dismissal (Mar. 2019) — same point; a dismissal signed by ZTE Corp. counsel would establish who was representing it.
  4. IPR2018-00235/-00236/-00237/-00238 petition papers — the mandatory notices will name ZTE Corp.'s PTAB counsel definitively.