[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-84479-en":3,"doc-seo-84479-105":28,"detail-sidebar-cat-0-en-105":89},{"code":4,"msg":5,"data":6},0,"success",{"doc_id":7,"user_id":8,"nickname":9,"user_avatar":10,"doc_module":4,"category_id":11,"category_name":12,"doc_title":13,"doc_description":14,"doc_content":15,"file_id":16,"file_url":17,"file_type":18,"file_size":19,"view_count":4,"is_deleted":4,"is_public":20,"is_downloadable":20,"audit_status":20,"page_count":11,"language":21,"language_code":22,"site_id":23,"html_lang":22,"table_of_contents":24,"faqs":25,"seo_title":13,"seo_description":14,"update_tm":26,"read_time":27},84479,687197100911,"Himbo","https://ap-avatar.wpscdn.com/avatar/a000239b6f1da00475?x-image-process=image/resize,m_fixed,w_180,h_180&k=1782698725881665579",8,"Research & Report","Performance Characterization of Frequency-Selective Wireless Power Transfer Toward Scalable Untethered Magnetic Actuation","Frequency-selective wireless power transfer enables independent actuation and control of multiple untethered robots in a shared workspace, yet the scaling limits within a given RF bandwidth remain unquantified. The study derives the relationship between resonator quality factor (Q-factor) and the maximum number of individually addressable LC resonant energy harvesters, then converts selectively harvested energy into mechanical motion. Theory and experiments show scalability depends primarily on Q-factor, supported by design equations and actuator demonstrations without cross-triggering.","Performance Characterization of Frequency-Selective Wireless Power Transfer Toward Scalable Untethered Magnetic Actuation  \nGabriel Cooper  \nDepartment of Electrical and Computer Engineering Texas Tech University Lubbock, USA  \nXiaolong Liu∗ Department of Mechanical Engineering Texas Tech University Lubbock, USA  \narXiv :2604 . 11645v2 [ ee ss . SY] 11 Jul 2026  \nAbstract—Frequency-selective wireless power transfer provides a feasible route to enable independent actuation and control of multiple untethered robots in a common workspace; however, the scalability remains unquantified, particularly the maximum number of resonators that can be reliably addressed within a given frequency bandwidth. To address this, we formulate the relationship between resonator quality factor (Q-factor) and the number of individually addressable inductor-capacitor (LC) resonant energy harvesters within a fixed radio-frequency (RF) spectrum, and we convert selectively activated harvested energy into mechanical motion. We theoretically proved and experimentally demonstrated that scalability depends primarily on the Qfactor. For this proof-of-concept study, we define effective series resistance as a function of frequency allocating bandwidths to discrete actuators. We provide design equations for scaling untethered magnetic actuation with Q-factor optimization. Resonator networks spanning bandwidths from 100 kHz to 1 MHz were analyzed to quantify how increasing the number of resonators affects independent addressability. We validated the approach experimentally by fabricating three centimeter-scale untethered actuators that selectively trigger the motion of mechanical beams at 734 kHz, 785 kHz, and 855 kHz. We also characterized the generated mechanical force and the activation bandwidth of each actuator, confirming that no unintended cross-triggering occurred.  \nIndex Terms—frequency-selective power transfer, LC resonators, magnetic actuation, radio-frequency spectrum, scalability  \nI. INTRODUCTION  \nSELECTIVE actuation of untethered magnetic robots op  \nerating in a shared workspace is a fundamental challenge because their actuation is inherently coupled through a common magnetic field source. Prior work has explored two main strategies for achieving selective actuation of magnetic robots, including the use of inhomogeneous magnetic fields to actuate robots at different spatial locations [1]–[5] and rotational stepout behavior in robots with different geometries or configurations [6], [7] . For example, global magnetic field dynamics exploit variations in magnetic material composition [6], robot geometry [7], [8], or robot placement in field gradients [1] to produce differentiated responses under a shared input field.  \nAlternative approaches have achieved localized magnetic manipulation using two-dimensional (2-D) electromagnetic coil *Corresponding author: Xiaolong Liu (email: [xiaolong.liu@ttu.edu](xiaolong.liu@ttu.edu)).  \nThis work was supported in part by the National Science Foundation under Grant No. 2512394, in part by the Texas Tech HEF New Faculty Startup Fund, and in part by the Texas Tech TrUE and McNair Scholar Programs.  \narrays [2]–[4], which generate spatially controllable fields in 2-D spaces and enable independent control based on robot position. Rotational step-out frequency based actuation has also been investigated using rotating magnetic fields to drive robots with different geometries that experience different fluid drag, including helical swimmers [9], [10], and block-shaped robots [7] . These approaches provide important starting points, but they remain difficult to scale and generalize.  \nBeyond approaches that rely on low frequency magnetic fields to achieve selective actuation of magnetic robots, wireless power transfer (WPT) techniques have been used to deliver RF magnetic energy to resonant circuits integrated into robotic devices, enabling actuation through mechanisms such as magnetic propulsion [11], heating shape me","cbCaijsdQuY4xGMW","https://ap.wps.com/l/cbCaijsdQuY4xGMW","pdf",5047158,1,"English","en",105,"# Introduction\n## Selective actuation in shared magnetic workspaces\n## Wireless power transfer approaches for robotic actuation\n## Motivation and research gap\n# Approach and contributions\n## Modeling Q-factor vs. addressable resonators\n## Frequency band selection (100 kHz to 1 MHz)\n## Experimental validation and performance characterization","[{\"question\":\"What problem does the paper address regarding frequency-selective wireless power transfer?\",\"answer\":\"The work targets the lack of quantified limits on how many untethered robots can be individually addressed within a fixed RF frequency bandwidth while using frequency-selective wireless power transfer.\"},{\"question\":\"How does the paper link resonator performance to scalability?\",\"answer\":\"It formulates and validates the relationship between resonator quality factor (Q-factor) and the maximum number of individually addressable LC resonant energy harvesters in a shared spectrum.\"},{\"question\":\"What experimental results were used to validate the approach?\",\"answer\":\"The paper fabricated three centimeter-scale untethered actuators that selectively trigger mechanical beam motion at 734 kHz, 785 kHz, and 855 kHz, and it characterized force and activation bandwidth while confirming no unintended cross-triggering.\"}]",1784195934,20,{"code":4,"msg":29,"data":30},"ok",{"site_id":23,"language":22,"slug":31,"title":13,"keywords":32,"description":14,"schema_data":33,"social_meta":84,"head_meta":86,"extra_data":88,"updated_unix":26},"performance-characterization-of-frequency-selective-wireless-power-transfer-toward-scalable-untethered-magnetic-actuation","",{"@graph":34,"@context":83},[35,52,66],{"@type":36,"itemListElement":37},"BreadcrumbList",[38,42,46,49],{"item":39,"name":40,"@type":41,"position":20},"https://docshare.wps.com","Home","ListItem",{"item":43,"name":44,"@type":41,"position":45},"https://docshare.wps.com/document/","Document",2,{"item":47,"name":12,"@type":41,"position":48},"https://docshare.wps.com/document/research-report/",3,{"item":50,"name":13,"@type":41,"position":51},"https://docshare.wps.com/document/performance-characterization-of-frequency-selective-wireless-power-transfer-toward-scalable-untethered-magnetic-actuation/84479/",4,{"url":50,"name":13,"@type":53,"author":54,"headline":13,"publisher":56,"fileFormat":59,"inLanguage":22,"description":14,"dateModified":60,"datePublished":60,"encodingFormat":59,"isAccessibleForFree":61,"interactionStatistic":62},"DigitalDocument",{"name":9,"@type":55},"Person",{"url":39,"name":57,"@type":58},"DocShare","Organization","application/pdf","2026-07-16",true,{"@type":63,"interactionType":64,"userInteractionCount":4},"InteractionCounter",{"@type":65},"ViewAction",{"@type":67,"mainEntity":68},"FAQPage",[69,75,79],{"name":70,"@type":71,"acceptedAnswer":72},"What problem does the paper address regarding frequency-selective wireless power transfer?","Question",{"text":73,"@type":74},"The work targets the lack of quantified limits on how many untethered robots can be individually addressed within a fixed RF frequency bandwidth while using frequency-selective wireless power transfer.","Answer",{"name":76,"@type":71,"acceptedAnswer":77},"How does the paper link resonator performance to scalability?",{"text":78,"@type":74},"It formulates and validates the relationship between resonator quality factor (Q-factor) and the maximum number of individually addressable LC resonant energy harvesters in a shared spectrum.",{"name":80,"@type":71,"acceptedAnswer":81},"What experimental results were used to validate the approach?",{"text":82,"@type":74},"The paper fabricated three centimeter-scale untethered actuators that selectively trigger mechanical beam motion at 734 kHz, 785 kHz, and 855 kHz, and it characterized force and activation bandwidth while 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