Futuristic multi-beam transmitarray antenna emitting colorful beams into a digital cityscape.

Beam Me Up: The Future is Now with Multi-Beam Transmitarray Antennas

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Beau Callahan in Tech & Innovation August 2025 • 5 min read.

"Unlock the potential of high-gain, cost-effective antenna technology and discover how Alternating Projection Method (APM) enhances multi-beam antenna design."


In an era where connectivity is king, the demand for efficient and high-performing antenna technology has never been greater. Enter the transmitarray antenna, a promising solution that combines the best features of array antennas and optical lenses. These antennas are lightweight, low profile, and free from feedline losses and feed blockages, making them ideal for satellite communication systems and other advanced applications.

Transmitarray antennas operate on a similar principle to reflectarrays, utilizing a feed and a flat, two-dimensional element array. This design compensates for phase differences, enabling the radiation of a high-gain pencil beam. However, unlike reflectarrays, transmitarray antennas eliminate blockage in the beam's path, offering a significant advantage in multi-beam applications.

Multi-beam antennas are essential in various fields, including satellite communications, electronic countermeasures, and multi-target radar systems. Traditional multi-beam antennas, such as lens, reflector, and phased array antennas, can be complex and costly. Transmitarray antennas offer a cost-effective alternative, using a single feed to achieve beam scanning and beamforming without additional expenses.

The Alternating Projection Method (APM): A Game Changer in Antenna Design

Futuristic multi-beam transmitarray antenna emitting colorful beams into a digital cityscape.

The Alternating Projection Method (APM) offers a novel approach to designing multi-beam transmitarray antennas. By treating the design as a general array synthesis problem, APM precisely calculates the phase distribution needed to optimize antenna performance. In this method, the excitation amplitude of each element is controlled by the feed's properties and location, while the excitation phase is achieved through phase compensation. APM searches for the intersection between two sets through an iterative process: the set of all possible radiation patterns and the set of ideal radiation patterns satisfying specific conditional limits.

The mathematical framework of APM involves complex equations and iterative processes. Essentially, the method seeks to find a radiation pattern that meets desired criteria by alternating projections between possible radiation patterns and ideal pattern constraints. This process continues until a stable solution is achieved, optimizing the antenna's performance. However, the method may converge to a local optimal value, which make it essential to choose an appropriate initial value.

Here’s a breakdown of how APM enhances multi-beam transmitarray antenna design:
  • Improved Gain: APM effectively increases the antenna's gain, boosting signal strength and overall performance.
  • Reduced Side-Lobe Levels: By minimizing side-lobes, APM ensures that the antenna focuses its energy in the desired directions, reducing interference.
  • Precise Phase Distribution: APM accurately calculates the required phase distribution, optimizing the antenna's radiation pattern.
  • Cost-Effective Solution: Compared to traditional methods, APM offers a cost-effective approach to achieving high performance.
To validate the effectiveness of APM, researchers designed a 13 GHz single-feed quad-beam transmitarray antenna with a compact size of 7.5 x 7.5 wavelengths. Simulations showed a peak gain of 19.3 dB and an efficiency of 29.6%. When compared to conventional design methods, the results demonstrated that APM not only calculates the phase distribution of the array but also significantly improves the antenna's performance, showcasing its potential for advanced communication systems.

Embracing the Future of Antenna Technology

The alternating projection method represents a significant step forward in the design of multi-beam transmitarray antennas. By offering improved gain, reduced side-lobe levels, and precise phase distribution, APM promises to unlock new possibilities in wireless communication and beyond. As technology continues to evolve, innovative approaches like APM will pave the way for more efficient, cost-effective, and high-performing antenna systems.

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.

Everything You Need To Know

1

What are transmitarray antennas, and what advantages do they offer over traditional antenna designs?

Transmitarray antennas combine the advantages of array antennas and optical lenses. They are lightweight, low profile, and free from feedline losses and blockages, making them well-suited for satellite communication systems and other advanced applications. They function similarly to reflectarrays, using a feed and a flat, two-dimensional element array to compensate for phase differences and radiate a high-gain pencil beam. Unlike reflectarrays, transmitarray antennas don't have blockage in the beam's path, which is an advantage in multi-beam applications.

2

How does the Alternating Projection Method (APM) specifically improve the performance of multi-beam transmitarray antennas?

The Alternating Projection Method (APM) enhances multi-beam transmitarray antenna design by improving gain, which boosts signal strength, and reducing side-lobe levels, which minimizes interference. APM also enables precise phase distribution, optimizing the antenna's radiation pattern. APM offers a cost-effective approach to achieving high performance compared to traditional methods. The method converges to a local optimal value, which make it essential to choose an appropriate initial value.

3

In what applications are multi-beam antennas essential, and how do transmitarray antennas provide a cost-effective alternative?

Multi-beam antennas are crucial in satellite communications, electronic countermeasures, and multi-target radar systems. While traditional multi-beam antennas like lens, reflector, and phased array antennas are complex and costly, transmitarray antennas offer a cost-effective solution. They use a single feed for beam scanning and beamforming, which avoids additional expenses. APM further enhances these transmitarray antennas.

4

Can you explain the mathematical framework and iterative process involved in the Alternating Projection Method (APM) for antenna design?

The Alternating Projection Method (APM) treats antenna design as a general array synthesis problem, precisely calculating the required phase distribution to optimize antenna performance. It involves an iterative process that searches for the intersection between all possible radiation patterns and ideal radiation patterns that meet specific conditional limits. The excitation amplitude of each element is controlled by the feed's properties and location, while the excitation phase is achieved through phase compensation.

5

What were the results of the 13 GHz single-feed quad-beam transmitarray antenna simulations, and how did they validate the effectiveness of APM?

Researchers designed a 13 GHz single-feed quad-beam transmitarray antenna with a compact size of 7.5 x 7.5 wavelengths. Simulations showed a peak gain of 19.3 dB and an efficiency of 29.6%. These results confirmed that APM effectively calculates the phase distribution of the array and significantly improves the antenna's performance compared to conventional design methods. APM shows potential for enhancing advanced communication systems.

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