30results about How to "Reduce void area" patented technology

The invention discloses a branch-loaded three-band composite microwave absorbing structure based on a frequency selective surface, belonging to the field of electromagnetic field and microwave communication. An upper dielectric layer, a frequency selection surface and a lower dielectric layer sequentially are arranged from top to bottom; a passive resonance unit of the frequency selective surfacecomprises a three-band absorbing structure and a square ring patch for absorbing a specific wave, the square ring patch being arranged on the three-band absorbing structure, the three-band absorbing structure comprises an arm-removed rectangular Jerusalem cross-shaped patch and a branch perpendicular to each other, the square ring patch and the Jerusalem cross-shaped patch are arranged in a centercoinciding manner, and the arm-removed rectangular portion of the Jerusalem cross-shaped patch is connected with four end points of the branch. The invention solves the problems that the angular stability and the microwave absorption performance of the cross-shaped structure in the existing frequency selective surface are poor, and the square ring structure can only absorb single frequency bands,and achieves the effects of improving the angular stability and absorbing waves in three frequency bands.

The invention provides a fin for a heat exchanger and the heat exchanger with the fin. The fin comprises a windowing part, a first windowing piece and a second windowing piece, wherein an approximately conical space is formed between adjacent windowing parts and is provided with a first end part and a second end part; the width of the first end part is smaller than that of the second end part; the first windowing piece is formed on the windowing part and is close to the first end part; the second windowing piece is formed on the windowing part and is close to the second end part; and the windowing width of the first windowing piece close to the first end part and extending into the first end part of the approximately conical space is smaller than that of the second windowing piece close to the second end part and extending into the second end part of the approximately conical space. Therefore, the windowing piece is wide enough to cover an empty area of a triangular area as much as possible, so that a wind field flowing through the fin is more uniform, and the heat transfer capability of the windowing piece is greatly improved.