• Reduce Conspicuity of In-Building Antenna with Transparent Solutions

    July 01, 2022

    Read time: 3 mins 41 secs

    5g antenna requirements

    What’s driving the need for 5g transparent antennas? Over the last several years, network operators have been densifying their networks to provide additional capacity and support new use cases. There has been significant new spectrum allocated by the FCC, which will result in more and sometimes larger antennas. The continuing trend in increasing data utilization, 80% of which is either originated or terminated indoors, makes in-building antennas particularly important as a present and future component of 5G communications infrastructure.

    Additionally, aesthetics is becoming a significant consideration in the proliferation of in-building antennas. Many venues and office spaces have increasingly strict aesthetic requirements for antennas and other network infrastructure.

    • transparent conductor film for antenna application
      3M antenna solution for in-building antennas is visually "transparent" and offers same performance.

      The Transparent Antenna Solution from 3M: Inconspicuous, robust, and efficient

      The 3M™ Transparent Conductor Film for antenna concealment allows antennas to be constructed with a transparent conductive film, reducing conspicuity of installed antennas. This antenna solution enables the creation of visually transparent antennas that helps networks meet the same performance requirements as a conventional antenna.

      There are several technologies available to create optically transparent, electrically conductive thin films. However, most are not suitable for 5G antenna applications. Analysis of the key characteristics of transparent conductor alternatives found that metal mesh worked better in antenna applications than other available alternatives. Low sheet resistance, high power handling capability and good PIM performance were key aspects of the selection criteria.

      Moreover, the typical surface roughness of the conductive traces is on the order of 100 nanometers (nm). This is much less than the skin depth at 6 GHz (0.85 mm in Cu) so the surface roughness does not significantly increase effective RF resistivity in the sub-6 GHz range. It is even less than a skin depth at 28 or 39 GHz (0.4 and 0.33 mm, respectively) so although 3M has not yet produced mmWave antennas, similar conductor film optimized for mmWave applications is on the 3M roadmap. 3M uses a highly conductive metal mesh material that allows for high efficiency and high gain antennas. By using this transparent material, you can achieve greater efficiency and gain compared to other transparent conductive film technologies.


    • transparent conductor film for antenna application
      3M™ Transparent Conductive Film applied to antennas in a conference room.

      And so, despite the fact that we’re using a mesh material that is actually 80% open area, it performs pretty similarly to the same antenna that uses solid copper.

      A surface treatment is applied to the mesh to reduce the reflected light and provide a neutral gray, as opposed to a copper color. This surface treatment also inhibits oxidation to provide improved environmental robustness.

      3M engineers directly measured local PIM performance over the surface of the 3M™ Transparent Conductor Film. The 3M™ Transparent Conductor film was placed on a stage with a near field probe in close proximity, with an IR camera focused on the film to measure localized temperatures. Since the local temperature increases with current density, measurements of PIM and temperature over the transparent antenna could be used to demonstrate that the highest current regions, i.e. those with highest local temperatures, were the source of the highest PIM.


    Summary of benefits of 3M™ Transparent Conductive Film

    • network infrastructure solutions

      High transparency: >80% open area

    • network infrastructure solutions

      High efficiency: <0.1 ohms per square sheet resistance

    • network infrastructure solutions

      High flexibility: sheet enables a wide variety of deployment options

    • network infrastructure solutions

      High power capability: 50W continuous power has been demonstrated

    The 3M business model is to provide 3M™ Transparent Conductive Film to antenna vendors, helping them camouflage antennas and enabling transparent antennas to meet performance objectives previously obtained with solid Cu designs.


    • 5g antenna design solution
      3M Patents for Transparent Antenna Application

      Highly conductive grid construction enables efficient antenna design and high visible light transmission.

      The conductive, transparent material from 3M enables 5G antenna camouflage with designs capable of supporting high input power. This is intended to allow the proliferation of 5G antennas in locations previously inaccessible for aesthetic reasons, thereby allowing wireless service providers to accelerate network deployments and improve in-building and outdoor coverage.

      For indoor applications, the antenna has aesthetic value. For outdoor applications, the antenna may be built into spotlight or streetlight lens covers.

      How could a customer access this 3M technology?

      End users will purchase their custom antenna patterns formed on the 3M™ Transparent Conductor Film, available as sheet or roll (future) formats. Please contact us to learn more.


    5G infrastructure requirements, build-out and cell densification will drive greater numbers of antenna installations. There is a demand for faster data transmission speed, up to multi-Gbps speeds and greater capacity, fueling a massive amount of IoT and other devices per square kilometer.

    Certain venues such as office spaces, retail, hi-rise buildings, health care facilities, and architectural spaces will value inconspicuous antennas for outdoor and in-building wireless. The 3M™ Transparent Conductor Film will allow antenna OEMs and system integrators to meet the need to provide high gain, low PIM inconspicuous antenna systems in those venues.

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