Slotted Waveguide Array
By cutting the slots along the waveguide broad-wall, the power can be radiated out to the free-space. However, although the impedance bandwidth of this kind of antenna is pretty good, but the main-beam angle is also steered off the zenith at the band-edge.
I am wondering are there any way to overcome this issues, means that make the main-beam of the slotted waveguide point to a fix angle over about 5% bandwidth.
Thanks.
You could try to feed the waveguide with a series feed. In other words use an E plane waveguide power divider and feed the array in the center of the guide. You will probably need an inductive window for matching the e plane divider
Try to short-circuit waveguide instead of use of matched load. You can also try to use long slot or combination of them. I saw(did) many researches about slotted waveguides, everything is possible..
I am not an antenna guy, but as I understand it, a slotted array has two elements to its design. One is the slot dimensions, which are normally resonated at mid band. The other is the spacing between the slots, which is usually some multiple of quarterwavelength. Seems like if you are having trouble at the bandedges you could play with those two parameters to compensate for it? ie tune the slots at one bandedge, but optimize the slot spacing at the other bandedge. yes/no?
You are talking about resonant slot, i.e. slot length is about half of free space lambda. It is well known and I guess there is nothing to get... Another thing is non resonant slot and systems of them. It is not traditional slotted antenna, it requires heavy numerical modelling, but for winglj I think this is the only way to get wanted parameters.