Futuristic transparent technology seamlessly integrated into a city.

The Future is Clear: Transparent Tech Could Change How We Interact with Devices

Soraya Malik in Tech & Innovation June 2025 • 3 min read.

"Scientists are developing transparent microwave absorbers, potentially revolutionizing everything from solar panels to security systems."

For decades, scientists have been trying to tame electromagnetic (EM) waves, seeking ways to absorb them for various applications. From reducing radar signatures on military equipment to improving wireless communication, the ability to control EM waves opens a world of possibilities. Early attempts to absorb these waves often resulted in bulky, fragile, or limited solutions, such as the Salisbury Screen and Jauman absorbers.

Enter the concept of circuit analog (CA) absorbers, a game-changer in the field. CA absorbers offer a path to create thinner, more effective absorbing structures. These structures typically involve a patterned resistive-conductive layer on a dielectric substrate, grounded to achieve optimal performance. However, even these advancements faced limitations in fabrication complexity, cost, or accuracy.

Now, researchers are pushing the boundaries even further by exploring optically transparent solutions. The goal? To create microwave absorbers that not only effectively manage EM waves but also allow light to pass through, opening doors to unprecedented applications.

A See-Through Solution: Interdigital Capacitance

Futuristic transparent technology seamlessly integrated into a city.

A groundbreaking study introduces a novel design for a polarization-insensitive, optically transparent broadband microwave absorber. This innovation hinges on the clever use of interdigital capacitance (IDC) structures. IDC involves creating a series of interweaving, capacitor-like fingers on a surface. These structures are made using indium-tin-oxide (ITO) resistive films, known for their commercial availability, affordability, and crucial characteristic – optical transparency.

Think of it like this: the top surface of the absorber is patterned with a square loop design, featuring inward-protruding fingers that create the interdigital capacitance. This intricate design sits atop a flexible substrate, separated by an air spacer from a continuous resistive film layer below. This unique arrangement allows for broadband absorption across a wide range of microwave frequencies.

Here's what makes this design so revolutionary:

Broadband Absorption: Effectively absorbs microwaves across a wide frequency range.
Optical Transparency: Allows light to pass through, making it suitable for various applications where visibility is essential.
Angular Stability: Performs consistently even when the angle of incoming microwaves changes.
Cost-Effectiveness: Utilizes commercially available and inexpensive materials.

The strategic use of IDC structures is the key. By carefully manipulating the geometry and parameters of the IDC, the researchers were able to fine-tune the top surface admittance, maximizing the impedance match and significantly boosting the absorption bandwidth. In essence, the IDC structure acts as a control knob, allowing engineers to precisely tailor the absorber's performance.

The Future of Absorption

This innovative design opens up a world of exciting possibilities. Imagine transparent EM shielding for observation windows, enhanced touch panel controls, or improved performance for RFID systems and solar cells. The ability to seamlessly integrate microwave absorption into transparent surfaces could revolutionize numerous industries and reshape the way we interact with technology. As research progresses, expect to see transparent absorbers playing an increasingly vital role in our technology-driven world.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1109/lawp.2018.2882584, Alternate LINK

Title: An Optically Transparent Broadband Microwave Absorber Using Interdigital Capacitance

Subject: Electrical and Electronic Engineering

Journal: IEEE Antennas and Wireless Propagation Letters

Publisher: Institute of Electrical and Electronics Engineers (IEEE)

Authors: Harsh Sheokand, Gaganpreet Singh, Saptarshi Ghosh, Janakarajan Ramkumar, Subramanian Anantha Ramakrishna, Kumar Vaibhav Srivastava

Published: 2019-01-01

Everything You Need To Know

How do circuit analog (CA) absorbers improve upon traditional microwave absorption techniques?

Circuit analog (CA) absorbers represent a significant advancement over earlier methods like Salisbury Screens and Jauman absorbers. CA absorbers offer thinner and more effective absorption structures by using a patterned resistive-conductive layer on a dielectric substrate. This design allows for better control and performance in absorbing electromagnetic waves compared to the bulkier and more limited early solutions. However, the complexity and cost of fabrication still posed challenges before the advent of optically transparent solutions.

What role does the interdigital capacitance (IDC) structure play in the function of this transparent microwave absorber?

The interdigital capacitance (IDC) structure is crucial to the functionality of this transparent microwave absorber. The IDC structure, made of interweaving capacitor-like fingers using indium-tin-oxide (ITO) films, allows for fine-tuning of the absorber's top surface admittance. By manipulating the geometry of the IDC, researchers can maximize impedance matching, which significantly boosts the absorption bandwidth. This is how the absorber achieves its broadband absorption capabilities.

Why is the use of indium-tin-oxide (ITO) films so important in the creation of these transparent microwave absorbers?

The use of indium-tin-oxide (ITO) films is essential because of its unique properties. ITO is commercially available and affordable, making the absorber cost-effective. More importantly, ITO is optically transparent. This transparency is critical because it allows light to pass through the absorber, enabling applications where visibility is necessary, such as transparent EM shielding for observation windows and enhanced touch panel controls. Without the optical transparency offered by ITO, the absorber's functionality would be severely limited.

What are the key characteristics that make this transparent microwave absorber design so innovative and widely applicable?

This novel design offers broadband absorption, meaning it can effectively absorb microwaves across a wide frequency range, enhancing its versatility. It also offers optical transparency, angular stability which ensures consistent performance, even with changing angles of incoming microwaves, and cost-effectiveness due to the use of affordable materials. These characteristics make the design applicable in observation windows, touch panels, RFID systems and solar cells.

What are the potential implications and applications of transparent microwave absorbers in shaping the future of technology and our interactions with it?

Transparent microwave absorbers could revolutionize various industries by enabling seamless integration of microwave absorption into transparent surfaces. For example, they can enhance touch panel controls, improve the performance of RFID systems and solar cells, and create transparent EM shielding for observation windows. This integration could lead to more efficient and aesthetically pleasing technology in our daily lives, reshaping how we interact with devices and infrastructure. Further research may lead to applications not yet imagined.