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In this work, we propose and demonstrate an integrated dual linearly polarized cavity-backed patch antenna, which is excited by a concurrent dual-mode substrate integrated waveguide (SIW) structure. For the first time, we have exploited the TE10 and TE20 modes of a traveling wave in a dual-mode SIW configuration to excite the horizontal and vertical polarizations of the patch antenna. The proposed methodology yields a low-profile structure with a high interport isolation thanks to the inherent symmetry of the structure. Measurement results indicate an isolation performing better than 42 dB over a 600 MHz impedance bandwidth of the antenna. Moreover, a methodology is developed to implement transitions from the dual-mode SIW to the two different TEM transmission lines for separate but concurrent excitations of the device. Detailed field and impedance analyses are presented to explain the operation principle of the proposed antenna, which are supported by an excellent agreement between the obtained measurement and simulation results. [ABSTRACT FROM AUTHOR]

The concept and feasibility of deploying higher-order space harmonics (HSHs) in 1-D periodic leaky-wave antennas (1-D periodic LWAs) is proposed, studied, analyzed, and demonstrated in this article. This can lead to the creation of multiband multibeam antennas (MBMBAs) with the capability of wide scanning ranges. To show the proposed concept, the excitation and flexibility of odd (n ε [−1, −3]) and even (n ε [−2, −4]) HSHs based on the analysis of a Brillouin diagram along with the effect of unit-cell geometrical structures of substrate integrated waveguide (SIW) for different propagating media are investigated. The proposed analysis is experimentally validated by prototyping and measuring a 1-D periodic LWA in SIW technology in which two HSHs (n ε [−1, −2]) are utilized for achieving a dual-band multibeam LWA with wide scanning range capability. In addition, a triple-band multibeam LWA design based on this concept is also analyzed and demonstrated where we take advantage of the characteristics of four HSHs (n ε [−1, −2, −3, −4]). Furthermore, the band edge issue of different stop-bands of HSH is also examined, and a method is proposed and used to address this issue where we use a quarter wavelength technique to overcome the matching problem at different frequencies related to different stop-bands of various HSHs (n ε [−1, −2, −3, −4]). Another design of a SIW-based 1-D periodic LWA is also discussed to extend and generalize the proposed concept in solving the mismatch issues of HSHs focusing on broadside radiation of the n = −2 space harmonic. The measured results are found to agree very well with their simulation and analysis counterparts. [ABSTRACT FROM AUTHOR]