The research paper "Flexible and Stretchable Microwave Filter Based on Substrate Integrated Plasmonic Waveguide" published in the journal IEEE Transactions on Microwave Theory and Techniques by the Flexible RF Technology Research Center

In 2024, the Flexible Radio Frequency Technology Research Center of Southeast University published a paper entitled "Flexible and Stretchable Microwave Filter Based on Substrate Integrated Plasmonic" in the journal IEEE Transactions 

on Microwave Theory and Techniques (impact factor: 4.5). The research paper "Waveguide" is described in detail below. 

As a key component of wireless wearable systems, radio frequency devices require high electromagnetic stability to ensure reliable communication quality. However, maintaining their performance under mechanical deformation presents a 

significant challenge.

To address the aforementioned issues, this study proposes a novel strategy for realizing a flexible, stretchable microwave filter based on a substrate integrated plasmonic waveguide (SIPW) structure. To maintain RF performance during 

deformation, we employ a shape-preserving strategy and integrate it with a serpentine interconnect via an "island bridge" by combining various mechanisms, a strip-shaped SSPP unit was developed.

The SSPP structure is etched onto the upper surface of a serpentine patterned substrate integrated waveguide (SIW), which is assembled with an elastic material to achieve a bandpass response. Simultaneously, an equivalent circuit model 

based on a two-dimensional transmission line was established to analyze the parasitic parameters induced by the serpentine structure on the radio frequency.

Analysis and experiments verified that the introduction of the serpentine microstructure slowed the phase velocity in the SIPW, thereby reducing the lateral dimension. Furthermore, due to the unique electromagnetic transmission mode of 

the SSPP/SIW and our special structural design, the proposed filter covers the X-band and maintains stable RF performance under normal conditions, 180° bending, 90° torsion, and 120% stretching, indicating its potential application value 

in stretchable electronic systems.

Figure 1  Flexible stretchable microwave filter

Paper Information

[1] Z.-H. Chen et al., “Flexible and Stretchable Microwave Filter Based on Substrate Integrated Plasmonic Waveguide,” IEEE Trans. Microwave Theory Techn., vol. 72, no. 10, pp. 5970–5982, Oct. 2024.