Nima Bayat-Makou

Substrate Integrated Horn Antenna Loaded With Open Parallel Transitions

The substrate integrated H-plane horn antenna has been struggling with very limited impedance bandwidth since its invention, which is coming from its natural aperture discontinuity. Apart from a variety of series transitions introduced so far, here, parallel transitions are applied to the antenna aperture in addition to narrow slots on the horn walls around the aperture to widen the antenna impedance bandwidth. It is shown that the depth of the transitions can easily determine the center frequency of the matching bandwidth. The new parallel transitions also reduce the antenna back radiation since they act as chokes around the horn aperture.

Substrate Integrated Horn Antenna With Uniform Aperture Distribution

A new substrate integrated horn antenna with hard side walls combined with a couple of soft surfaces is introduced. The horn takes advantage of the air medium for propagation inside, while having a thickness of dielectric on the walls to realize hard conditions. The covering layers of the air-filled horn are equipped with strip-via arrays, which act as soft surfaces around the horn aperture to reduce the back radiations. The uniform amplitude distribution of the aperture resulting from the hard conditions and the phase correction combined with the profiled horn walls provided a narrow beamwidth and −13 dB sidelobe levels in the frequency of the hard condition, which is validated by the simulated and measured results.

Substrate integrated hard horn antenna

The horn antennas are probably the simplest and widely used microwave antennas. They are basically a device which provides a transition between waves propagating in a transmission line and wave disseminating in an unbounded medium such as free space. The bulky geometry of traditional horns has always been a limitation for these antennas to be used in compact form at high frequencies. In recent years, the invention of substrate integrated waveguide (SIW) technology has revolutionized the employment of planar horn antennas integrated into microwave and millimeter-wave circuits.

Cavity matching of high dielectric constant SIW H-Plane horn antenna

A simple SIW H-plane horn antenna with a loaded open cavity is introduced. The new combination of the SIW H-plane horn and the open cavity results in a wide and constant impedance bandwidth, which has been hard to achieve by a single SIW horn antenna. Besides matching improvement, the new configuration results in higher gain with radiation pattern focused in antenna aperture. The longitudinal size of the structure is kept as the simple SIW horn; however, it is three times thicker than the simple horn.

Hard boundary condition realization for substrate integrated horn antennas

A substrate integrated realization of hard boundary conditions is presented inside the substrate integrated H-plane horn antenna. The normal soft conditions of the substrate integrated horn antenna are changed to hard conditions by changing the inside permittivity of the horn in a 5-step perforation procedure. The proposed design of the horn results in a uniform aperture distribution with improved directivity in comparison with the regular substrate integrated horn.

Back Radiation Suppression for Substrate Integrated H-Plane Horn Antenna

A new multi-layer antenna structure including simple substrate integrated H-plane horn antenna with a couple of soft surfaces is introduced. The planar strip-via soft surfaces are located at top and bottom of the substrate integrated horn to stop the aperture radiated waves contributing to antenna back radiation. The new antenna structure exhibits more than 13 dB improvement in front-to-back ratio at design frequency when compared to simple substrate integrated H-plane horn antenna.

Substrate integrated horn antennas with improved aperture efficiency

The tapered aperture distribution of the substrate integrated horn antenna always limits its aperture efficiency and widens the antenna beam width. Therefore, the integrated H-plane horn has rarely been considered for the applications where fan-beam types of radiation pattern are required. Here, the amplitude distribution of the integrated horn aperture has been improved to be almost uniform by the three methods of applying hard boundary conditions to the lateral walls of the horn. Among these three methods, air-filled integrated horn in which the internal substrate is removed by keeping a thickness of the dielectric on the walls shows wider improvement over the bandwidth.

SIGW dual level H-plane horn antenna for millimeter waves

The modified configuration of substrate integrated H-plane horn is presented which is very versatile that enables the horn to have a thin thickness of its planar feed line while having a thick radiating aperture at millimeter wave frequencies. This configuration is based on substrate integrated gap waveguide (SIGW) technology in which the propagating printed ridge is separated with the periodic structure. In this design, the level of the separated ridge has the same thickness of the thin microstrip feeding. The upper level is coupled with a transition to the lower level which is integrated with periodic structure.

Aperture controlled substrate integrated h-plane horn antenna

The H-plane integrated horn antenna equipped with hard internal E-walls, and soft external H-walls is introduced. The lateral hard walls of the horn resolve the tapered nature of the horn aperture and provide the antenna with uniform aperture distribution at the hard frequency band. The external soft surfaces around the aperture suppress the aperture scattered waves in order to reduce the antenna back radiation.

Millimeter-Wave Substrate Integrated Dual Level Gap Waveguide Horn Antenna

Substrate integrated H-plane horn antenna design is introduced based on elevated substrate integrated gap waveguide (E-SIGW) configuration. The E-SIGW topology allows designing the horn from two substrates of different thicknesses. A thin substrate for the feed line to eliminate the radiation losses and a thicker one for the radiating aperture. The proposed configuration allows the H-plane horn aperture to be three times thicker than the feed line substrate, which is not possible with the conventional substrate integrated waveguide technology. The transition between the horn layers enhances the matching bandwidth without any aperture modification. The outer surface of the horn around its aperture is loaded with soft surfaces realized by transverse strips. As a result, more symmetric fan beam radiation patterns with suppressed back lobes are achieved.