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In this article a compact planar fed substrate integrated waveguide (SIW) based self-multiplexing (SM) antenna for hexa-band operation is proposed for the first time. Six different patches with planar 50Ω feed lines are designed and attached to the top side of the rectangular SIW cavity. The antenna operates at six different frequencies (5.33 GHz, 5.76 GHz, 6.31 GHz, 6.86 GHz, 7.34 GHz, and 7.8 GHz) simultaneously. The antenna attains 4.5 dBi, 4.94 dBi, 4.9 dBi, 5.12 dBi, 6.12 dBi, and 6.6 dBi peak gain at respective resonant frequencies. Port relocation, stepped patches, and additional vias are exploited to maintain isolation (> 23 dB) between any two ports. The front-to-back ratios (FTBRs) are between 10 dB to 20 dB and Co-Pol to Cross-pol ratios are between 10 dB to 29 dB. The design supports single-variable independent frequency tuning for all six patches and eligible for wide range of applications. The proposed design is fabricated and results are validated through measurement. The antenna is suitable for planar microwave devices.

A novel and compact all planer-fed self-triplexing patch antenna is designed and demonstrated for triple-band operation simultaneously. The model is comprised of one substrate-integrated waveguide (SIW) cavity, three planar ports, and one modified I-shaped slot. The proposed antenna is designed in a simple three-step method to achieve improved self-triplexing property. In the first step, a rectangular slot is created and its position is altered to obtain initial isolation (>20 dB) between any two ports. Secondly, the same slot is modified to an I-shape, which creates three patches facing three different ports and radiates at three different frequencies (4.14, 6.1, and 8.32 GHz) with minimum isolations above 28.4 dB. In the third step, one input-port is off-centered to obtain port isolation tradeoff so that isolation between any two ports is better than 30.8 dB. Importantly, the proposed design also supports easy individual frequency tuning using single variable. For demonstration purpose, the antenna is fabricated and characterized. The proposed planar antenna is very simple, compact, and feasible for handheld microwave devices.

In this article a simple compact (0.28 λ g 2) substrate integrated waveguide (SIW) based self-diplexing antenna is proposed. The self-diplexing antenna consists of an SIW cavity, two off-centered stepped patches and two feeding ports. The whole design is developed in a simple three step process. In first step two patches of different lengths are created on the top side and fed separately by two 50Ω feedlines to operate at two different frequencies. In second step, to maintain acceptable isolation the ports are equally off-centered in opposite directions. In the last step, to further improve the isolation the patches are modified to stepped shape. The proposed antenna operates at 5.23 GHz (for WiFi) and at 5.8 GHz (for ISM band) independently/simultaneously with peak gain of 5.22 dBi and 5.1 dBi respectively. At both the resonant frequencies the antenna possesses > 18 dB front-to-back-ratio. Importantly, the design allows each resonant frequencies to be tuned separately using single design parameter. A prototype of the prosed self-diplexing antenna is fabricated and characterized. Good agreement is obtained between the simulated and measured results. As per its performance and compactness the proposed antenna is a suitable candidate for indoor WiFi and ISM band applications.

In this article, a novel design of compact cavity‐backed slot antenna based on substrate integrated waveguide (SIW) technology is presented for dual‐frequency communication services. A single layer printed circuit board is applied to implement the proposed antenna. The bowtie‐ring slot engraved on the SIW square cavity is excited using two orthogonal microstrip feed lines to operate at two distinct frequencies (6.62 GHz and 11.18 GHz). The proposed antenna allows each of these frequencies to be designed independently. A prototype of the proposed cavity‐backed antenna that radiates at both 6.62 GHz and 11.18 GHz is fabricated and measured. The port isolation better than 29.3 dB is achieved by utilizing the transmission zeros (TZs), which are produced due to the orthogonal feed lines, TE110 mode and coupling between the TE120 and TE210 modes. The measured peak gains of the proposed diplexing antenna are 5.77 dBi and 5.81 dBi at lower and upper resonating frequencies, respectively. The proposed dual‐frequency antenna exhibits the front‐to‐back‐ratio (FTBR) and cross‐polarization level greater than 26 dB and 21 dB, respectively, at both resonating frequencies.

A compact high-isolation self-diplexing antenna is designed on a single-layered substrate integrated waveguide (SIW) cavity for dual-frequency communication in C-band. The antenna design procedure is straightforward. The antenna is backed by an SIW cavity for possible low back-lobe radiation and easy circuit integration. One rectangular and one triangular patch are created on the top-side of the SIW cavity to radiate at 4.18 GHz and 7.8 GHz respectively. Two planar inset-feed lines orthogonal to each other, are employed to excite the resonator. The inset depths of the feedlines are designed to obtain low interference and high isolation. The antenna achieves peak gain of 5.88 dBi and 6.62 dBi at lower and upper resonant frequencies respectively. The antenna supports independent frequency tuning-design and easy frequency-ratio control. The proposed design is fabricated on a RT/Duroid 5870 substrate and is characterized for validation.