ATL | Antenna Technology Laboratory

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  Design of small antennas and antenna arrays

  The use of arrays with multiple antennas has become essential for adaptive...

  The use of arrays with multiple antennas has become essential for adaptive beamforming in advanced wireless communication systems. Typically, arrays are used to adjust the direction of beams and nulls by multiplying complex weights to antenna ports for more reliable communication links in a multipath environment. This beamforming capability can be extended to estimate the direction of signals and mitigate the effects of interference; however, a growing demand for more effective beamforming capability in handheld devices with limited space has led to several technical challenges from an antenna engineering standpoint. First, active element patterns are distorted by strong mutual coupling between the array elements. Second, these distorted radiation characteristics result in lower estimation accuracy, increased ambiguity, and poor resolution in adaptive beamforming operations. Although various miniaturization techniques have been applied to the radiating elements in an effort to employ more antennas in a limited space, the antennas experience an additional gain reduction with an undesired frequency shift due to the narrow matching bandwidth, which cannot exceed the fundamental bandwidth limit. Thus, there has been a growing demand for altering the traditional approach of multiple-antenna arrays to solve these technical challenges, which allows for improving the beamforming performance with a miniaturized aperture size.

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  Phased and time-modulated array antennas

  Traditionally, various beamforming systems based on phased arrays are...

  Traditionally, various beamforming systems based on phased arrays are widely adopted in military and civil applications, however, in searching for less complex alternatives, active research has been stimulated for time-modulated array antennas. Charactersitscs of the TMA antennas are listed below:

  • Phase shifters are replaced to RF switches that can be used to steered the array patterns.
  • The use of RF switches results in different weights with respect to the period and the duty.
  • Advantages of using the TMA are in lighter weights, lower costs, and lower complexity, which may carry greater potentials for more advanced future wireless communications technologies.
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  Optimization of antennas and array configurations

  Optimization techniques are extremely important in the designing process of...

  Optimization techniques are extremely important in the designing process of antennas and antenna arrays to improve the overall system performances by taking into account antenna characteristics, mutual coupling effects, platform effects, etc. We mainly focus on the genetic algorithm, a.k.a. GA, and are also working very hard to develop a more efficient optimization process based on the machine learning process.

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  Beamforming hardware implementation

  Implementation of beamforming hardware is essential for antenna engineers...

  Implementation of beamforming hardware is essential for antenna engineers to verify the feasibility of the developed antennas and antenna arrays through field tests.

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  Microwave sensing and metasurfaces

  Demands on microwave sensing and metasurfaces have increased due to...

  Demands on microwave sensing and metasurfaces have increased due to the ease of fabrication and cost efficiency. ATL is recently focusing on this topic to collaborate with others for interdisciplinary research. Possible applications can be extremely high-Q resonances for sensing, such as bio-related technologies.