A W-Band Multi-Feed Low-Profile Transmitarray Antenna Using Orthogonal Slot Element

This paper presents a low-profile transmitarray using multi-feed technology. The element of the transmitarray adopts two orthogonally arranged slots on the bottom and upper layer of the cavity as received and transmitted structure, and is constructed using only a single-layer laminate. The element achieves 1-bit phase state by locating the transmitting slots at two different positions which are symmetrical. The element has an extended bandwidth by incorporating a center shorting pin in the cavity. Four slots excited by one-to-four metal waveguide feeding network are introduced to feed the transmitarray, effectively reducing the height-to-diameter ratio (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H/D</i>). Finally, a low-profile transmitarray antenna with 24 × 24 elements is designed, fabricated, and measured. The overall antenna has an aperture size of 13.09 13.09 λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">₀</sub> × 13.09 λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">₀</sub>, and an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H/D</i> ratio of 0.18. Measured results indicate that the proposed antenna achieves a peak gain of 24.5 dBi and a 3-dB gain bandwidth of 12.2%. The proposed antenna is a promising candidate for spaceborne and satellite communications.