A wide-band waveguide phase-shifter

Cosec 2 hybrid travelling/resonant antenna for maritime surveillance applications

“…2, where symmetry is exploited. The couplings of the directional couplers Li_k, where i refers to the division level and k to the kth divider, are calculated by (1) and (2) and shown in Fig. 3.…”

“…The antenna exploits hybrid architecture [1] as it combines a corporate feed BFN [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] made up of cascaded directional couplers and true-time delay phase shifters, and directive radiating elements, given by slotted rectangular waveguides in a travelling wave configuration. The antenna features constant detection for targets approaching from the horizon at a fixed height, owing to a square cosecant vertical beam distribution of the radiated power [21,22].…”

“…The main design steps can be summarised as follows: (1) definition of the circuit BFN, which includes design of (i) power dividers, (ii) phase shifters, (iii) coupler terminations (iv) and folding, (2) definition and design of the radiators by means of a slotted waveguide in a travelling wave configuration, featuring a cosec 2 radiation pattern, (3) simulation, fabrication, and measurement of the whole array. The above points (1), (2), and (3) are discussed in Sections 2, 3, and 4, respectively.…”