Prior art — US Patent 11876548

To identify the most relevant prior art for US patent 11876548, I will examine the patent citations listed within the patent itself. The patent document provides a "Prior art keywords" section and explicitly references several U.S. Patents in its "BACKGROUND OF THE INVENTION" and "DETAILED DESCRIPTION" sections.

Based on the provided patent text, the following are the most relevant prior art references:

1. U.S. Pat. No. 7,369,828 (Shamsaifar, owned by Paratek Microwave)

Full Citation: U.S. Pat. No. 7,369,828 to Shamsaifar
Publication/Filing Date: The patent mentions it was "discussed in U.S. Pat. No. 7,369,828" and also cites "U.S. Pat. No. 7,369,829" in connection with a method described in 7,369,828. The earliest priority date listed for US11876548 is August 14, 2008, so prior art would typically predate this. The patent text itself does not explicitly provide the publication or filing date for 7,369,828, but mentions it was "recently" advanced.
Brief Description: This patent describes a device and method for tuning two different cellphone antennas (one for high band, one for low band) using active elements like voltage-tunable varactors controlled by a DC voltage supply. Each antenna is described as comprising a substrate, a patch element, at least one voltage tunable varactor, a DC bias point, an RF input, a temperature sensor, and a ground plane. It specifically discusses a quad-band antenna covering cellular telephone frequencies (824-894 MHz, 880-960 MHz, 1710-1880 MHz, 1850-1990 MHz; GSM850, EGSM, GSM1800, PCS 1900).
Potential Anticipation (35 U.S.C. § 102): This patent potentially anticipates aspects of claims related to actively tuning antennas for multiple frequency bands, particularly claims concerning the use of active elements (like tunable capacitors/varactors) and a controller for tuning. Specifically, it could anticipate elements within Claims 3, 5, 9, 11, 14, and 16, which discuss a tuner for tuning a steerable antenna with active elements and a processor for controlling said tuning. However, US11876548 distinguishes itself by allowing a single antenna to be used for simultaneous transmission (or reception) for multiple bands, which the '829 patent (and by extension '828 as discussed in relation to it) did not contemplate. The novelty in US11876548 lies in its expansion of active antenna tuning to enable simultaneous multi-band use with a single antenna.

2. U.S. Pat. No. 7,397,329

Full Citation: U.S. Pat. No. 7,397,329 (assigned to Paratek Microwave).
Publication/Filing Date: Not explicitly stated in the provided text.
Brief Description: This patent is mentioned as being assigned to Paratek Microwave, in the context of tunable dielectric materials like Parascan (barium strontium titanate, BSTO). It is broadly related to the underlying technology for tunable dielectric materials used in tunable capacitors.
Potential Anticipation (35 U.S.C. § 102): While contributing to the background of tunable materials, this patent likely provides foundational technology rather than direct anticipation of the claimed device or method in US11876548, particularly the steerable antenna aspects and user-avoidance features. It could be relevant as general prior art for the concept of tunable active elements used in the tuners.

3. U.S. Pat. No. 7,202,747 (Agile employees)

Full Citation: U.S. Pat. No. 7,202,747, “Self Tuning Variable Impedance Circuit for Impedance Matching of Power amplifiers.”
Publication/Filing Date: Not explicitly stated in the provided text.
Brief Description: This patent, produced by Agile employees, uses BST tunable capacitive material to affect a resonance change in a tunable circuit. It relates to self-tuning variable impedance circuits for impedance matching.
Potential Anticipation (35 U.S.C. § 102): Similar to '329, this patent describes fundamental technology for active tuning components. It contributes to the general knowledge of active antenna tuning and impedance matching. It would serve as general prior art for the tunable components mentioned in Claims 3, 5, 9, 11, 14, and 16, but not necessarily the specific application of steerable antennas for user avoidance or simultaneous multi-band operation with a single steerable antenna as claimed in US11876548.

4. U.S. Pat. No. 7,012,483 (Agile employees)

Full Citation: U.S. Pat. No. 7,012,483, “Tunable Bridge Circuit.”
Publication/Filing Date: Not explicitly stated in the provided text.
Brief Description: Also produced by Agile employees, this patent uses a BST tunable capacitive material to affect a resonance change in a tunable circuit.
Potential Anticipation (35 U.S.C. § 102): Similar to '747, this patent focuses on tunable circuit elements and would be considered general prior art for the active tuning mechanisms described in US11876548, rather than directly anticipating the unique combination of features for steerable, user-avoiding, multi-band antennas.

5. U.S. Pat. No. 7,676,194 to Rappaport (U.S. patent application Ser. No. 10/919,515)

Full Citation: U.S. Pat. No. 7,676,194 to Rappaport, describing ultrawideband repeaters.
Publication/Filing Date: Filed as U.S. patent application Ser. No. 10/919,515. The provided text indicates this patent "now issued U.S. Pat. No. 7,676,194". The priority date for US11876548 is 2008-08-14. This patent is incorporated by reference in US11876548.
Brief Description: Describes Ultrawideband repeaters. The text notes that the current invention (US11876548) could make use of this.
Potential Anticipation (35 U.S.C. § 102): This patent appears to be cited more for its potential application in conjunction with the disclosed invention rather than direct anticipation. While it relates to UWB systems, it does not describe the specific steerable antenna device with user avoidance or multi-band simultaneous operation as the core invention of US11876548. It may be relevant as background art in the broader field of wireless communication systems and UWB applications where the steerable antenna device could be deployed.

Other general prior art references for tunable dielectric materials (cited as background for Paratek/Agile technology):

U.S. Pat. No. 5,312,790 to Sengupta, et al. entitled “Ceramic Ferroelectric Material”
U.S. Pat. No. 5,427,988 by Sengupta, et al. entitled “Ceramic Ferroelectric Composite Material-BSTO-MgO”
U.S. Pat, No, 5,486,491 to Sengupta, et al. entitled “Ceramic Ferroelectric Composite Material-BSTO-ZrO2”
U.S. Pat. No. 5,635,434 by Sengupta, et al, entitled “Ceramic Ferroelectric Composite Material-BSTO-Magnesium Based Compound”
U.S. Pat. No. 5,830,591 by Sengupta, et al. entitled “Multilayered Ferroelectric Composite Waveguides”
U.S. Pat. No. 5,846,893 by Sengupta, et al, entitled “Thin Film Ferroelectric Composites and Method of Making”
U.S. Pat. No. 5,766,697 by Sengupta, et al. entitled “Method of Making Thin Film Composites”
U.S. Pat. No. 5,693,429 by Sengupta, et al. entitled “Electronically Graded Multilayer Ferroelectric Composites”
U.S. Pat. No. 5,635,433 by Sengupta entitled “Ceramic Ferroelectric Composite Material BSTO-ZnO”
U.S. Pat. No. 6,074,971 bye Chiu et al. entitled “Ceramic Ferroelectric Composite Materials with Enhanced Electronic Properties BSTO Mg Based Compound-Rare Earth Oxide”

These Sengupta patents describe various tunable dielectric materials. They are relevant as underlying technology for the active tuning elements mentioned in US11876548 but do not directly anticipate the system-level claims regarding steerable antennas for user avoidance or simultaneous multi-band operation. Their relevance is to the material science behind the tunable components used within the tuners.

Summary of Potential Anticipation:

The primary distinction emphasized in US11876548 from prior art like U.S. Pat. No. 7,369,829 (which is described as not contemplating the present invention) is the ability to use a single antenna for simultaneous transmission (or reception) for multiple bands, and the concept of a steerable antenna avoiding radiating towards a person or object. Therefore, while the individual components and general concepts of active tuning and multi-band antennas may find roots in the cited prior art, the combination of these features, particularly the steerability for user avoidance and simultaneous multi-band operation on a single (potentially steerable) antenna, forms the basis of novelty for US11876548. The prior art cited by the patent itself (such as U.S. Pat. No. 7,369,828) generally deals with separate antennas for different bands or active tuning for a single band, not the integrated and "steerable" aspects for user safety and simultaneous multi-band use above 10 GHz as claimed.