On the Performance Analysis of Pinching-Antenna-Enabled SWIPT Systems

Bingxin Zhang; Han Zhang; Kezhi Wang; Kun Yang; Yizhe Zhao

REVIEW 3 major objections 5 minor 11 references

On the Performance Analysis of Pinching-Antenna-Enabled SWIPT Systems

T0 review · 3 major / 5 minor · reviewed 2026-08-05 · deepseek-v4-flash

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Pith's one-line read Closed forms predict energy-rate trade-off for pinching-antenna SWIPT systems under three waveguide placements.

desk verdict The energy half of this pinching-antenna SWIPT paper drops the path-loss coefficient μ from Eq. (1), making the harvested-energy formulas off by roughly six orders of magnitude; the rate half is sound and the application is new. read the letter →

arxiv 2509.03836 v1 pith:HKBU3ROR submitted 2025-09-04 eess.SY cs.SY

Bingxin Zhang , Han Zhang , Kun Yang , Yizhe Zhao , Kezhi Wang This is my paper · ORCID

classification eess.SYcs.SY

keywords pinchingantennaSWIPTaverageharvestedenergyachievablerateenergy-ratetrade-offtimeswitchingpowersplittingclosed-formanalysis

verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper claims that a pinching-antenna—an antenna element clipped onto a dielectric waveguide—can support simultaneous wireless information and power transfer whose average performance is predictable by elementary closed forms. A base station with one pinching antenna serves a user uniformly located in a rectangle, and the paper proposes three waveguide deployments: along an edge, through the center, or along the diagonal. For each deployment the antenna slides to the point on the waveguide closest to the user, and the paper derives the distribution of that optimal distance. From the distance distribution it obtains exact integrals for average harvested energy under linear and nonlinear energy-harvesting models, a Jensen upper bound for the nonlinear model, and exact average achievable rate. A sympathetic reader would care because this turns a deployment-design problem into a comparison of simple formulas, letting the energy-rate trade-off be chosen without exhaustive simulation.

What carries the argument

The load-bearing object is the distribution of L*_ν, the distance from the optimally repositioned pinching antenna to a uniformly random user, characterized in Lemmas 1 and 2. The optimal position is the orthogonal projection of the user onto the waveguide: the y-coordinate is 0 or Dy/2 for the edge and center schemes, and the projection onto the diagonal with slope k = Dy/Dx for the diagonal scheme. The closed forms come from integrating three functions of this distance—1/L*^2 for linear harvested energy, the logistic saturation function of 1/L*^2 for nonlinear harvested energy, and log2(1 + μγ̄/L*^2) for achievable rate—against the one-dimensional distance density. Arctangent and logarithm

What would settle it

A direct experiment would mount a pinching antenna on a waveguide at known height h over a rectangular area, reposition the antenna to the optimal point for each receiver location, and compare measured received power against μPt E[1/L^2]. A systematic distance dependence different from 1/L^2, or a mismatch beyond measurement noise at any receiver position, would falsify the channel model behind Lemmas 3 to 7.

Watch

Extended reading notes

Core claim

The central claim is that, under the free-space point-source channel of Eq. (1), the random distance between the optimally positioned pinching antenna and a uniformly located user has a tractable distribution for all three deployments: for the edge and center schemes the squared distance follows a shifted uniform-root law, and for the diagonal scheme it follows a piecewise square-root density. Integrating against these densities yields closed forms (Lemmas 3, 4, 6, and 7) for average harvested energy and average achievable rate, and a Jensen bound (Lemma 5) for the nonlinear energy-harvesting model. The paper positions this as the first analytical performance model for pinching-antenna-enabl

Load-bearing premise

The results rest on the free-space point-source model of Eq. (1): the pinching antenna radiates isotropically with no waveguide attenuation, no antenna pattern, no small-scale fading or interference, and it can be moved instantly to the exact projection point on the waveguide—if any of these fail, the derived distance distributions and closed forms no longer describe the system.

Editorial extensions

If this is right

The energy-rate trade-off can be optimized over the time-switching factor α and power-splitting factor β without Monte Carlo simulation, because both objectives are explicit functions of these parameters.
Under the nonlinear energy-harvesting model, the Jensen upper bound replaces simulation with a one-line evaluation; at high transmit power the bound reflects the saturation behavior of the rectifier.
Deployment choice is geometry-dependent: the paper's simulations find the diagonal scheme best in a square room, while the center scheme can overtake it in an elongated room—the closed forms make this comparison immediate.
The diagonal projection reduces a two-dimensional positioning problem to a one-dimensional quadratic minimization, so the distance probability density remains one-dimensional and analytically integrable.
The same distance distribution underlies both energy and rate expressions, so the three Lemmas form a shared toolbox for any future SWIPT protocol that depends only on the chosen antenna position.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

Editorial check: the printed energy formulas (14), (16), and (19) omit the path-loss prefactor μ = c^2/(16π^2 f_c^2) that appears in Eq. (1); if that constant is intended, the linear-energy formulas simply scale by μ, but the nonlinear Jensen bound is not linear in μ, so the printed NLM curves would shift non-uniformly.
The same distance-distribution machinery should extend to multiple pinching antennas on one waveguide or to a user moving along a known trajectory, with the distance density becoming a mixture over time.
Because the diagonal-deployment projection has a particularly clean CDF, curved or segmented waveguides with invertible projection-distance CDFs may admit analogous closed forms.
A direct comparison of these ideal-channel predictions with measurements using a real directive pinching antenna would quantify the combined loss due to antenna pattern, waveguide leakage, and repositioning latency.

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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Desk Editor's Note

read the letter

The core issue is exactly what the stress-test note says: Eq. (2) and Eq. (4) define average harvested energy and incident power without the μ from Eq. (1). Since received power is μPt/d², Lemmas 3–5 and the NLM bounds are dimensionally inconsistent with the paper's own signal model. At 28 GHz this is a factor of ~1.4 million, so the numerical energy results are meaningless as reported. The Monte-Carlo curves match the formulas, but they simulate the same wrong model, so they don't rescue anything.

The genuinely new part is the application of pinching antennas to SWIPT with three waveguide deployment schemes (edge, center, diagonal). The distance CDFs in Lemmas 1–2 are correct, and the DDS derivation in Appendix A is a nice geometric argument. I checked the rate integrals in Lemmas 6–7; they retain μ inside the log and the algebra appears sound. So the rate side of the paper holds up.

Two additional soft spots, both minor compared with the μ omission. The Jensen upper bound in Eq. (18) is called an upper bound, but the logistic function Φ(Pin) is not concave over the whole domain—it's convex for Pin below the inflection point. So the claimed bound is not guaranteed. Also, for the diagonal scheme, the paper asserts the projection always lies on the waveguide segment; it does, but only because their coordinate scaling forces x* to remain in [0,Dx]. Worth stating explicitly.

Who gets value from this? Researchers working on pinching-antennas or SWIPT who want analytical benchmarks for deployment choices. The rate formulas and the distance distributions will be useful even after the energy expressions are fixed. The error is embarrassing but mechanical: reinsert μ into Pin and the energy integrals, and the framework becomes coherent. The paper deserves a serious referee, not a desk reject, because the core setup is new and the rate analysis is solid.

My recommendation: send it to review, but with a clear note that the energy derivations must be corrected before acceptance. If the authors fix the μ omission and either prove concavity or relabel the Jensen result as an approximation, the paper would be a reasonable contribution to a narrow subfield.

Referee Report

3 major / 5 minor

Summary. This paper studies a single-user SWIPT system in which a pinching antenna is moved along a rectangular waveguide to minimize the distance to a uniformly located UE. Three waveguide placements are considered (edge, center, diagonal), together with a hybrid TS/PS protocol. For each placement the authors derive closed forms for the average harvested energy under a linear model and an upper bound under a non-linear logistic model, as well as closed forms for the average achievable rate, based on the distribution of the optimized antenna-UE distance. Monte-Carlo simulations are reported to validate the expressions and to exhibit an energy-rate trade-off.

Significance. If the derivations were correct, this would be a useful first analytical framework for pinching-antenna SWIPT, providing directly computable averages for deployment planning and insight into the energy-rate trade-off. The paper's distance-distribution approach (Lemmas 1-2) is transparent, and the rate integrals in Lemmas 6-7 are algebraically detailed and include the free-space path-loss factor consistently. The main strength is that the closed forms are explicit enough to be checked. However, the energy half of the framework is not valid as written because the path-loss coefficient defined in Eq. (1) is omitted from Eq. (2), Eq. (4), and Lemmas 3-5, and the so-called NLM upper bound depends on an unproved concavity assumption. These issues affect the central claim—prediction of harvested energy and the energy-rate region—and require correction before the contribution can be assessed.

major comments (3)

[Eqs. (1)-(4), Lemmas 3-5] Eq. (1) defines the received amplitude with factor sqrt(mu), so the received power is mu Pt / ||psi_p - psi_u||^2. Yet Eq. (2) defines the average LM harvested energy as E[alpha beta eta Pt / L^2] and Eq. (4) defines Pin = beta Pt / L^2; the factor mu is absent. Consequently Lemma 3 (14), Lemma 4 (16), and Lemma 5 (19) are missing mu everywhere and are dimensionally wrong (Pt/L^2 has units W/m^2 rather than W). At fc = 28 GHz, mu ~ 7.3e-7 m^2, so the reported energy values are too large by about 1.4 million. The rate analysis in Lemmas 6-7 correctly includes mu inside the SNR, so this is an internal inconsistency, not merely a modeling convention. Fix by inserting mu in (2), (4), and all energy/Pin expressions, and rerun the energy simulations and figures.
[Lemma 5 and Eq. (18)] The NLM upper bound applies Jensen's inequality E[Phi(Pin)] <= Phi(E[Pin]). This requires Phi to be concave on the support of Pin. The logistic model (3) is a sigmoid: it is convex for Pin < b and concave for Pin > b. With the stated parameters (b = 2.9 microW) and typical received powers, the operating range is not guaranteed to be concave, so the claimed inequality direction is not established and may even be reversed. The paper needs to prove concavity over the relevant range, restrict the parameter regime, or replace the "upper bound" by a valid bound. As written, the NLM energy results are not supported.
[Fig. 2 and numerical validation] Fig. 2 reports agreement between simulation and analysis for harvested energy. If the Monte-Carlo code uses the same definition Pin = beta Pt / L^2 as Eq. (4), the agreement validates only the algebra of the internally inconsistent energy model, not the physical model of Eq. (1). After correcting the missing mu, the numerical curves and any conclusions about absolute harvested energy and the energy-rate trade-off must be regenerated. The qualitative ranking of the three deployment schemes may survive because mu is a common multiplicative factor in the LM case, but the NLM numerical values and saturation behavior may change.

minor comments (5)

[Eq. (7) and Lemmas 1-3] Eq. (7) writes L3 = ||psi_p,3 - psi_u|| but the right-hand side is the squared distance; a square root is missing. The same convention recurs in Lemmas 1-3, where the support of the PDF is [h^2, h^2 + (...)^2], indicating that l is L^2 rather than L. Please define the squared distance as a separate random variable, e.g., X = L^2, and use it consistently in (9)-(10), (12)-(13), and the proofs of Lemmas 3-4.
[Abstract and grammar] The abstract contains grammatical errors, e.g., "we studies the performance" and "the pinching-antenna." The paper should be carefully proofread throughout.
[Simulation parameters in Section IV] The parameters 'a = 100 / microW' and 'b = 2.9 microW' imply that Pin is expressed in microW, but Eq. (4) defines Pin as beta Pt / ||...||^2, which has units W/m^2 (and should be W after adding mu). State the unit conventions used in the Monte-Carlo implementation, otherwise the NLM numerical evaluation is ambiguous.
[Captions of Figs. 2-3] The labels S1/S2 and C1/C2 are defined only in the body text; please define them in the captions for readability.
[Lemma 5 proof] The one-line Jensen argument is omitted; please include it and state explicitly the assumed regularity conditions, given the concavity issue raised above.

Circularity Check

0 steps flagged · score 0.0 of 10

No circularity identified: the closed-form results are direct expectations under the stated model; the flagged issues are internal inconsistencies (dropped μ, 1/L vs 1/L²), which are correctness concerns, not circular reasoning.

full rationale

Walked the derivation chain in Sections II–III and Appendices A–B. The average harvested energy and rate closed forms are obtained by integrating the PDFs of the minimum distance L* against 1/l or log2(1+μγ̄/l); these are direct expectations under the stated uniform-user assumption. No parameter is fitted to the simulated curves, no target quantity is fed back as an input, and no load-bearing claim is justified by the authors' own prior work. The only author self-citation is [1], a general survey in the introduction, which is not used to justify any derivation. The Jensen upper bound (18) is explicitly an upper bound, not a purported exact prediction, so it is not circular. The noted problems—Eq. (2) omitting the path-loss coefficient μ defined in (1), and Lemmas 3 and 4 proofs integrating 1/l while (2) requires 1/l²—are internal-model inconsistencies/correctness errors, not circular reductions. Similarly, the DDS optimal position (8) is the orthogonal projection onto the waveguide line, a standard minimization of (7), not an assumed result. Rate expressions in Lemmas 6–7 retain μ inside the SNR terms. Hence there are no circular steps.

Assumptions & free parameters 0 free parameters · 4 assumptions · 0 invented entities

The central results rest on the LoS point-source channel, exact repositioning, uniform user placement, and a Jensen concavity assumption. No new physical entities are introduced; the pinching antenna itself is prior art from [5]. No parameters are fitted to data, but the energy formulas omit mu, which is an error rather than a fitted parameter.

assumptions (4)

domain assumption Free-space point-source LoS channel with no waveguide, pattern, or fading losses (Equation (1)).
All distance distributions and averages are computed for received power mu*Pt/d^2 from the pinching antenna to the user; any real pinching-antenna directionality or waveguide leakage changes these formulas.
domain assumption The pinching antenna is repositioned exactly to the distance-minimizing projection for every user realization (Section III).
The optimal positions psi_p,1*, psi_p,2*, and psi_p,3* are assumed achievable with no positioning error, quantization, or movement cost; this underpins the CDF/PDF lemmas.
domain assumption The user location is uniform over the rectangle [0,Dx] x [0,Dy] (Section II).
The CDFs and all expectations are with respect to this uniform law; other user distributions require re-derivation.
domain assumption The logistic NLM parameters phi, a, b describe the rectifier and Phi is concave over the support of Pin (Equations (3) and (18)).
The Jensen upper bound requires concavity of Phi over the support of Pin. With mu retained, Pin lies far below the inflection b=2.9 uW, where the logistic is convex, so the stated bound is not guaranteed.

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Cite this review

Pith. "Pith review of On the Performance Analysis of Pinching-Antenna-Enabled SWIPT Systems." pith.science (2026). https://pith.science/paper/HKBU3ROR

@misc{pith2026250903836,
  author       = {Pith},
  title        = {Pith review of: On the Performance Analysis of Pinching-Antenna-Enabled SWIPT Systems},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/HKBU3ROR}},
  note         = {Machine review of arXiv:2509.03836}
}

read the original abstract

In this paper, we studies the performance of a novel simultaneous wireless information and power transfer (SWIPT) system enabled by a flexible pinching-antenna. To support flexible deployment and optimize energy-rate performance, we propose three practical pinching antenna placement-schemes: the edge deployment scheme (EDS), the center deployment scheme (CDS), and the diagonal deployment scheme (DDS). Moreover, a hybrid time-switching (TS) and power-splitting (PS) protocol is introduced, allowing dynamic adjustment between energy harvesting and information decoding. Under each deployment strategy and the transmission protocol, closed-form expressions for the average harvested energy and average achievable rate of a randomly located user equipment (UE) are derived based on the optimal positioning of the pinching-antenna. Numerical simulations confirm the accuracy of the theoretical analysis and illustrate the trade-off between rate and energy harvesting under different schemes.

Figures

Figures reproduced from arXiv: 2509.03836 by the authors.

**Figure 2.** The average harvested energy versus the transmit power. [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗

**Figure 3.** The average achievable rate versus the transmit power. [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗

Figures from the paper (2 more)

**Figure 4.** Figure 4: Energy-rate trade-off under three waveguide deployment schemes. [PITH_FULL_IMAGE:figures/full_fig_p004_4.png]

**Figure 5.** Figure 5: The ground projection of the pinching antenna. [PITH_FULL_IMAGE:figures/full_fig_p005_5.png]

Discussion (0). Continue with ORCID to comment.

Reference graph

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J. Hu, K. Yang, G. Wen, and L. Hanzo, “Integrated data and energy com- munication network: A comprehensive survey,” IEEE Communications Surveys & Tutorials , vol. 20, no. 4, pp. 3169–3219, 2018

work page 2018

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Q. Wu and R. Zhang, “Intelligent reflecting surface enhanced wireless network via joint active and passive beamforming,” IEEE Transactions on Wireless Communications , vol. 18, no. 11, pp. 5394–5409, 2019

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Fluid antenna systems,

K.-K. Wong, A. Shojaeifard, K.-F. Tong, and Y . Zhang, “Fluid antenna systems,” IEEE Transactions on Wireless Communications , vol. 20, no. 3, pp. 1950–1962, 2021

work page 1950

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L. Zhu, W. Ma, and R. Zhang, “Modeling and performance analysis for movable antenna enabled wireless communications,” IEEE Transactions on Wireless Communications , vol. 23, no. 6, pp. 6234–6250, 2024

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A. Fukuda, H. Yamamoto, H. Okazaki, Y . Suzuki, and K. Kawai, “Pinching antenna-using a dielectric waveguide as an antenna,” NTT DOCOMO Tech. J. , vol. 23, no. 3, pp. 5–12, 2022

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