A novel dual-band patch antenna operating at 28/38 GHz is proposed for multiple-input multiple-output (MIMO) communication systems in this paper. The antenna utilizes substrate integrated waveguide (SIW) transmission line as the feed by means of a coupling slot on the SIW. A square patch antenna functions as the radiator for 28 GHz. The inductive loading, which presents as a pair of shorting pins in this design, achieves the impedance matching for 28 GHz-band. Etched on the square patch, the proposed H-shaped slot makes the radiator to performance as an antenna containing two radiating arms and thus introduces another resonant frequency at 38 GHz. Directions of the surface current on the paired arms are identical and produce a reasonable radiation pattern for 38 GH-band. Simulated results declare that the antenna achieves an S 11 <; -10 dB bandwidth of 27.6 - 28.5 GHz (relative bandwidth of 3.2%) and 36.9 - 38.9 GHz (relative bandwidth of 5.3%), while simulated gain is 9.0 dBi at 28 GHz and 5.9 dBi at 38 GHz, respectively. Measured results have verified the feasibility and correctness of the proposed dualband antenna, which indicate that the antenna is a promising candidate for MIMO communication systems at millimeter-wave (mmW) band.

In this paper, a systematic research campaign on eighth-mode substrate integrated waveguide (EMSIW) filters is reported. The sizes of these EMSIW resonant cavities are only one-eighth or one-sixteenth of a conventional SIW resonant cavity. Two different coupling topologies, i.e., electric coupling and magnetic coupling, are employed between two EMSIW resonant cavities, which are analyzed theoretically via the response of the structure and the relationship between the cavities. Both coupling topologies enable structural variations that possess advantages and flexibility of the second-order EMSIW bandpass filters (BPFs) designing. By utilizing these basic coupling mechanisms, multilayer board technology, and other practical techniques, a class of triple-order SIW BPFs with the merits of compact size and high selectivity are demonstrated. Specifically, several triple-order EMSIW BPFs composed of pure EMSIW cavities or comprised by combining EMSIW and quarter-mode SIW cavities are simulated, fabricated, and measured for verification.

In this paper, a new class of shielded half-mode substrate integrated waveguide (SD-HMSIW) and shielded quarter-mode substrate integrated waveguide (SD-QMSIW) filtering power dividers (FPDs) have been presented. The proposed prototypes are capable of splitting/combining power and selecting frequency simultaneously. The SD-HMSIW and SD-QMSIW resonant cavities combine the features of compact size, high quality factor and low loss. To the best of author’s knowledge, it is the first time employing the shielded SIW structure for FPD designs. Six prototype circuits with pure or hybrid SD-HMSIW/SD-QMSIW resonators are designed and fabricated to validate the proposed concept. Multilayered structures are implemented to minimize the dimensions of the FPDs further. Transmission zeros distributing near the operating passband are introduced by cross coupling mechanism. Both measured and simulated results indicate that the proposed FPDs with shielded SIW structures exhibit not only filtering performance, but also good magnitude and phase imbalance characteristics in the operating frequency band.

A compact filtering power divider composed of two quarter‐mode circular cavities based on the substrate integrated waveguide is proposed. Two extra perturbing via‐holes added in each side of the quarter‐mode circular cavity achieve a selective bandpass filtering response and improve the performance of the upper stopband. The proposed FPD operates at 9.1 GHz with a 3 dB fractional bandwidth of 19.8%. The insertion loss in operating band is < 1.6 dB and the input return loss is better than 16 dB. The amplitude and phase imbalances between the two outputs are measured better than 0.6 dB and 3.5°, respectively. The measured results exhibit good agreement with the simulated ones.

In this paper, a multi-mode resonator (MMR) overlapping mode control technique is proposed to realize dual-band substrate-integrated waveguide (SIW) bandpass filters (BPFs). A pair of via perturbations and two kinds of slotlines are introduced to control the overlapping modes. Five resonant modes TM110 (a pair of degenerate modes), TM210 (a pair of degenerate modes) and TM020 are perturbed to realize the dual-band filters. The degenerate modes can be rearrange by the via perturbations, and the overlapping modes can be adjusted by the slotlines. Thus, two kinds of dual-band filters can be realized in a single resonant cavity. Then a two-cavity dual-band filter is proposed to realize better out-band suppression and return loss performance. The proposed two-cavity dual-band BPF is synthesized, designed, fabricated, and measured, realizing the 3-dB fractional bandwidth (FBW) of 6.1% and 7.7% at Q-band and V-band, respectively.

In this letter, a novel dual-band substrate integrated waveguide (SIW) filter with the perturbed circular cavity is presented. By introducing three kinds of metallic via perturbations combining different angles of feeding lines, five resonant modes TM ₀₁₀ , TM ₁₁₀ (a pair of degenerate modes), and TM ₂₁₀ (a pair of degenerate modes) are perturbed to design the proposed filter. Thus, a dual-band filter with three transmission poles in the first passband and two transmission poles in the second passband is realized in a single circular cavity. Multiple transmission zeros are generated to increase the out-band performance. Then, a two-cavity dual-band filter is proposed by cascading two identical circular cavities, which shows better out-band suppression and return loss performance. The proposed dual-band filters are designed, fabricated, and measured in a standard printed circuit board (PCB) process at the $Q$ -band and the $V$ -band.