Anotace:
This paper presents a novel slotted array for dual-band and circular-polarized applications. Two different propagation modes within a Substrate Integrated Waveguide (SIW), TE10 and TE20, feed at the same time two pairs of slots, aimed at different frequency bands. The pairs are properly placed to be illuminated by an only propagation mode, whereas the magnetic field of the other propagation mode presents a null. Unlike many dual-band slot arrays, this novel antenna holds the same beam tilt for both frequency bands by a new method, which is only feasible through the use of two propagation modes. A dual-mode transition, based on a double microstrip input, allows to excite both propagation modes within the SIW, and it can be fed by a novel single layer dual-band phase shifter with a different shift at each frequency. A square patch is placed over each pair of slots to increase the coupled energy per element, resulting in a low polarization loss and high performance compact antenna at 3.5GHz and 6GHz for dual-band TX/RX systems at C-Band.