This paper proposes a dual-polarized endfire phased array for 5G handset devices at 28 GHz. The proposed 4-element array has low profile of 1.1 mm, small clearance of 2.7 mm, and symmetric patterns in the vertical plane. The array element is fed by Substrate Integrated Waveguide (SIW), which works as a waveguide (WG) antenna with vertically polarized radiation pattern. Two transition plates are introduced to improve the impedance matching of the WG antenna. The horizontal polarization is generated by exciting one of the transition plate as an antenna. The other transition plate is modified as a group of triangle strips to minimize its reflection to the horizontal radiation patterns. A -10-dB frequency bandwidth of 5.3% and a -6-dB bandwidth of 25% are achieved, overlapping between the vertical and horizontal polarization. The array scanning angle is from -54∘ to 44∘ at 29 GHz for both polarization. Within the scanning range, the endfire gain varies from 7.48 to 8.14 dBi for the horizontal polarization, whereas from 4.49 to 8.05 dBi for the vertical polarization. Good agreements between simulations and measurements are well achieved and shown in this paper.

A novel phase corrected substrate integrated waveguide (SIW) H-plane horn antenna with embedded metal-via arrays is presented. The SIW horn is divided into four subhorns by three metal-via arrays inside the horn. A uniform phase distribution of EM field across the horn aperture is achieved by adjusting the lengths and positions of the metal-via arrays. The proposed horn antenna has a compact profile, and its simulated gain is 7.50 dBi at 35.5 GHz, whereas the simulated gain of a traditional horn antenna without the metal-via arrays is 6.38 dBi. When measured, the gain of the proposed horn antenna is 7.87 dBi at 35.5 GHz, whereas the gain of the traditional horn antenna is 5.58 dBi. Good agreement between the simulated and the measured results is obtained.

In this paper, the use of a dispersive prism with a triangular shape is proposed to reduce the dispersive radiation nature of a leaky-wave antenna (LWA) in groove-gap waveguide technology. The operation of gap waveguide technology is based on the use of metallic pins that act as an artificial magnetic conductor, so the electromagnetic fields are confined and guided in the desired directions. To control a leaky-wave radiation of these confined fields is possible by tailoring the height of the pins, its periodicity, and the waveguide width. This radiation, as in any conventional LWA, is dispersive, leading to beam squint as the frequency is varied. Here, we mitigate this beam squint by using a prism made of dispersive pins and choosing appropriately their periodicity and height. With this prism, the leaky-wave radiation is focused into one single direction in a wide frequency band. This concept is demonstrated with a prototype designed to radiate at $\varphi =41^\circ $ with a central frequency of 12 GHz and the high gain of 16.5 dBi. A 22% frequency bandwidth for the 3 dB realized gain at $\varphi =41^\circ $ is achieved, and the main radiating direction, with half-power beamwidth of 5°, steers only ±0.5° from 11.4 to 13.4 GHz.

This communication introduces a modified substrate integrated waveguide (SIW), the gap SIW, and deduces an approximate closed-form expression for calculating its effective width, taking into account the fringing and coupling fields around the gap. As an immediate application, this new structure is used to correct the phase distribution of an H-plane SIW horn antenna. The achieved quasi-uniform distribution results in a greatly enhanced antenna gain without deteriorating the bandwidth. To further improve both radiation and impedance matching, printed tapered-ladder transitions are introduced in front of the horn aperture. Software optimization confirms the possibility of simultaneously achieving an excellent phase correction (and hence increased gain) and a good impedance matching in a probe-excited horn antenna model. Measurements on a homemade prototype validate the design strategy. The final compact Ka-band planar horn antenna achieves an enhanced gain of 10.3 dBi at 34 GHz, with an impedance bandwidth of 20%.

New communications systems require high-speed data transfer and need high frequency, wideband, and directive antennas. Leaky-wave antennas are a desirable type of antennas for millimeter and submillimeter waves, since they can produce a high directive radiation with a single feeding. The latter is an enormous advantage to reducing the cost and losses at high frequency. Despite these advantages, their dispersive nature inherently produces a beam squint effect in their radiation patterns. Here, we propose the use of a lens that compensates for the dispersion of the leaky wave, making the overall antenna broadband. This concept is demonstrated in substrate integrated waveguide technology at Ka-band, and the lens is integrated in the same technology. Full-wave simulations and experimental results are presented to demonstrate the potential of our proposal. Our manufactured prototype has more than 20% frequency bandwidth for the 3-dB pattern at φ = 31°, and the main radiating direction steers only ±0.5° from 35 to 40 GHz with a half-power beamwidth of 8°.

A novel substrate-integrated waveguide (SIW) horn antenna with partially detached broad walls is designed and analyzed. The conventional SIW horn antenna suffers from narrow-operating bandwidth, which mainly results from the mismatch at the horn aperture between the substrate and the free space. However, the detachment of the broad walls makes the left substrate not only act as wave-guiding structure but also impedance transformer, which brings much size reduction in comparison with conventional SIW horn antenna. Moreover, the substrate with graded dielectric constants distributed in the propagating direction is realized through perforating air-vias with different diameters to further improve the radiation performance. Results indicate that the proposed antenna operates from 17.7 to 26.7 GHz with a nearly constant peak-radiating gain between 8 and 9 dBi at end-fire direction. Stable end-fire radiation patterns can be realized in the whole operating band. Above all, the proposed technology makes it compact to design SIW horn antenna of high performance without extra extension after the aperture of the radiating horn.