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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.

This paper presents a miniaturized tri- and quad-band power divider (PD)based on substrate integrated waveguide (SIW). By adopting different types of modified circular complementary split-ring resonators on the top surface of SIW, multiple passbands are generated propagating below the SIW cut-off frequency. The working principle is based on evanescent mode propagation that decreases the operating frequency of the PD and helps in the miniaturization of the proposed structure. The operating frequency of the proposed PD can be individually controlled by changing the dimensions of the resonator. To verify the proposed concept, a tri-band and a quad-band PD exhibiting 3 dB equal power division at 2.41/3.46/4.65 GHz and 2.42/3.78/4.74/5.8 GHz are designed using the full-wave simulator, validated through circuit model, fabricated and experimentally verified. The measured results agree well with the simulations. The proposed PDs have good performance in terms of reasonable insertion loss, isolation, minimum amplitude and phase imbalance, smaller footprint, easy fabrication and integration. The size of the fabricated prototype is 18.3 mm × 8.4 mm, which corresponds to 0.205λg × 0.094λg, λg being the guided wavelength at the first operating frequency.

This paper communicates the design and experimental validation of dual-band SIW power dividers (single-stage and double-stage) with arbitrary power division. The dual-band power dividers are developed for WiMAX (3.5 GHz) and WLAN (5 GHz) applications. The proposed SIW power dividers are realized by a rectangular cavity, two rows of metallic-vias and one pair of unequal complementary split-ring resonators (CSRRs). Two resonating frequencies are produced below the waveguide cut-off frequency due to the unequal CSRRs etched-out on the top-surface of the cavity, which results in size reduction. To realize arbitrary power division, two output-ports are configured asymmetric with respect to input-port. The power division is varied by altering the distance between the two output-ports. Finally, two compact dual-frequency power dividers (single-stage and double-stage) working at 3.5 and 5 GHz are designed and validated through fabrication and measurement. The fabricated prototype exhibits dual-band operation, compact size (0.027 λ g 2 ${\lambda }_{g}^{2}$ ), good magnitude imbalance, return loss and isolation.

This letter presents the design of compact triple- and quad-band power dividers (PDs) based on substrate integrated waveguide (SIW) technology. The proposed PDs are designed as a rectangular cavity, one pair of unequal complementary split-ring resonators (CSRRs) and U-shaped slots (USSs). Initially, a dual-frequency SIW PD is implemented using unequal CSRRs on the top surface of the SIW cavity. This dual-frequency PD is converted into triple-band and quad-band operations by employing USSs on the bottom surface of the cavity. The center frequencies of the proposed PDs are controlled by varying the dimensions of CSRRs and USS. To demonstrate the proposed concept, triple- and quad-band PDs are designed, fabricated, and tested. The measured responses are very much consistent with the simulated one. The overall sizes of the proposed triple- and quad-band PDs are $0.03\lambda _{g} ^{2}$ and $0.02\lambda _{g} ^{2}$ , respectively. The proposed PDs feature compact size, triple- and quad-band operation, good return loss, and isolation.

In this article, substrate integrated waveguide (SIW) filter with compact size and wide out-of-band rejection is designed for 5G (sub-6 GHz) applications. To achieve the proposed filter responses, ...

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.

In this paper, a novel design of highly compact power divider employing substrate-integrated waveguide (SIW) is proposed for dual-band applications. The double-ring asymmetric complimentary split-ring resonators (CSRRs) are utilized to obtain dual-band operation. The asymmetric double-ring CSRRs create mixed magnetic and electric coupling resulting two distinct resonating frequencies which exhibits bandpass behaviour below the resonating frequency of the cavity. The resonating passbands can be designed individually by varying the dimensions of the proposed CSRRs. In addition, the position of output ports can be varied to achieve arbitrary power division. To demonstrate the proposed analysis, three prototypes (two equal power division and one unequal power division) of dual-band SIW power dividers are designed and fabricated. Measurement performance provides a good consistency with that of simulated one. The circuit areas of the fabricated prototypes 1, 2 and 3 excluding microstrip transitions are 0.053λg2, 0.088λg2 and 0.033λg2, respectively. The proposed design process exhibits dual-band performance with smaller circuit-area, suitable isolation and hence appropriate for dual-band communication services.

In this paper, a novel design of compact substrate integrated waveguide (SIW) diplexer with square cavities for C-band applications is presented. This diplexer is working on evanescent-mode propagation and operating below the cut-off frequency of the cavity. First, the filtering response of triangular-slot loaded on one square cavity surface is investigated. This response of the cavity is then applied on two cascaded filters to obtain the diplexer characteristics. To validate the concept, a narrow band filter and diplexer are designed and simulated. The insertion losses at lower and upper passbands centered at 6.16 GHz and 7.72 GHz are obtained as 0.83 dB and 0.77 dB, respectively. The proposed diplexer provides a fractional bandwidth more than 5.1% at each passband with high isolation better than 22 dB. These features show that the proposed diplexer is a suitable candidate for C-band application.

This letter presents a novel design approach for implementation of miniaturized quad-band branch-line crossover. To achieve quad-band operation, each 90° microstrip-line of a single-band crossover is replaced with a novel quad-band transmission-line. The proposed structure is developed by connecting one coupled-line between two series transmission-lines. The even–odd mode technique is applied to derive closed-form formulas. For experimental verification, a quad-band crossover operating at 0.9 GHz, 2.48 GHz, 3.82 GHz and 5.4 GHz for GSM, WiFi, 5G and WLAN applications, respectively, are designed, fabricated and demonstrated. The measurement results of the fabricated prototype at four distinct frequency bands exhibit similar characteristics to that of a conventional single-band prototype. In addition, the fabricated prototype achieves a size miniaturization of 67.35% when compared to the conventional single-band crossover.

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.