Abstract: In this letter, two slot arrays with high radiation efficiency are proposed based on the empty substrate integrated waveguide (ESIW) technology. The arrays consist of four FR-4 substrate ...

Gracie Muehlberger wrote letters to her future self and stored them in a multicolored trinket box on her dresser. Her notes, penned when she was 13 and signed “Gracie from the past,” bubbled with ...