Експериментальне дослідження коефіцієнта стоячої хвилі за напругою прямокутного хвилеводу з поздовжньою щілиною за зміни її розмірів та довжини штиря збудження

Abstract

Wave-slot antennas are widely used in on-board radio systems. The requirements for such antennas are to reduce weight and size indicators and power losses in the antenna feed system. To fulfill these requirements, it is possible, in particular, to use a rectangular waveguide with a longitudinal slot (if it is convenient to cut the slot along the surface current lines), as a weakly directional radiator or an element of a slotted waveguide antenna array. In this case, a reactive pin is used to excite the longitudinal slot and adjust it. For the practical implementation of such an antenna, it is important to ensure appropriate matching of the slot excited by the pin, both with the waveguide and with free space. Therefore, in the article, the possibility of reducing the voltage standing wave ratio in a rectangular waveguide with a longitudinal slot and the excitation pin was studied by experimental method. Experimental data are obtained on the change in the voltage standing wave ratio in a rectangular waveguide with a change in the dimensions of the longitudinal slot (length, width), the length of the excitation pin, and the position of the short-circuited copper plug which completes the waveguide. In particular, for a rectangular waveguide with a cross-sectional size of 23 mm by 10 mm, operating on Н10 main type of oscillations, graphs were obtained to specify the dependence of the voltage standing wave coefficient on the change in the length of the excitation pin for different slot lengths and fixed values of its width of 1.98 cm and 2.97 cm. The optimal dimensions of the slot and the length of the excitation pin to ensure the minimum voltage standing wave ratio (no more than 3) with a fixed position of the short-circuited copper plug are summarized in the table. With an excitation pin length of 0.7 cm, a slot length of 1.3 cm, a slot width of 1.5 mm, and a position of a short-circuited copper plug of 1.98 cm, the voltage standing wave ratio does not exceed 1.4. The results of experimental studies do not contradict the existing theories and can be used to design and adjust slot antennas in a rectangular waveguide, which are excited by a pin.