Non-Resonant Slotted Waveguide Antenna Design Method

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  • Author: By Michal Grabowski, Cobham Antenna Systems

In this paper a non resonant Slotted waveguide antennas have been the subject of extensive research for several years. These structures are commonly used in microwave transmitter and receiver devices. Such antennas radiate energy from feeding waveguide to a free space through several slots cut in a broad or narrow wall of a rectangular waveguide. Special interest in such antennas is caused by their planar and compact structure, high power handling and electrical parameters, such as high efficiency, relatively wide frequency band and good return loss. Their additional advantage is the ability to combine vertical slotted waveguides as phased array with shaped and electronically switched multi-beam radiation patterns, which enables the observation of many “moving targets” at the same time. Slotted waveguide array antennas can be realized both as resonant and non-resonant according to the wave propagation inside the waveguide (respectively standing or travelling wave). Among antennas from the non-resonant subgroup it is possible to distinguish antennas that work over and below resonant frequency (respectively distance between adjacent slots smaller or larger than the half waveguide wavelength). Non-resonant slotted waveguide array antennas, which are tipped with a waveguide termination, provide a feature of squint (not occurring for resonant ones). This effect causes an angle deviation of an end fire direction from a normal to the antenna aperture. Additionally, this deviation is dependent upon an operating frequency and is described as: In this paper a nonresonant slotted waveguide antenna design method is presented. Non-Resonant Slotted Waveguide Antenna Design Method: Inclusive Internal and External Electromagnetic Mutual Coupling Between Slots By Michal Grabowski.