Javad Pourahmadazar

X-band substarte integrated waveguide Rotman Lens

This paper presents a novel substrate integrated waveguide (SIW) for X-band sensing applications. It employs a SIW Rotman Lens (RL) as a beam switching network. A prototype lens is designed with 7 beam ports and 9 array ports. The simulated results around the frequency of 10-GHz demonstrate the validity of the proposed design and scanning capability over±24°. The design process of the proposed microwave lens for X-band sensing application is implemented in SIW technology. In this work, a new lens with SIW technology is proposed to feed an array antenna to generate multiple beams. Since multiple beams are possible to be simultaneously obtained by reusing the antenna aperture, frequency and multiple functions can be incorporated in a single electronic system. The simulated results around the frequency of 10-GHz demonstrate. The proffered lens, which is comprised of seven beam ports, nine array ports and eight dummy ports, was designed to operate at the center frequency of 10-GHz, on an RO5880 substrate with electric permittivity of 2.2 and thickness of 0.508mm. The proposed Rotman lens is designed for a nine linear array radiation elements. Seven beam ports were implemented in the proposed lens to generate seven beams at 0°, ±8°, ±16° and ±24±, respectively.

X-band substarte integrated Rotman Lens with ±24° scanning capability

This paper presents a novel substrate integrated waveguide (SIW) for X-band sensing applications. It employs a SIW Rotman Lens (RL) as a beam switching network. A prototype lens is designed with 7 beam ports and 9 array ports. The simulated results around the frequency of 10-GHz demonstrate the validity of the proposed design and scanning capability over (-24°, +24°). Throughout this paper, the design process of the proposed microwave lens for X-band sensing application is demonstrated in details.

Supershaped metamaterial unit-cells using the gielis formula

In this paper, the superformula introduced by Gielis is used as a generator of various shapes for metamaterial unit-cells. This formula has already been used to describe the complicated shapes found in nature. Some of these designs are simulated and it is shown that they are capable of providing resonances in their frequency response. The superformula has a lot of potential for creative shape designs such as multiband and compact unit-cells that can be used for advance antenna and microwave applications.

A steerable Yagi-Uda array antenna using a substrate integrated waveguide Rotman lens

This paper presents a novel steerable 8-12 GHz Yagi-Uda array antenna using substrate integrated waveguide (SIW). It employs an integrated waveguide structure microwave Lens as a beam forming network (BFN). The proposed microwave lens is Rotman type integrated lens in substrate. A prototype lens is designed with 7 beam ports, 9 array ports, and 8 dummy ports. A 10 GHz SIW-fed Yagi-Uda antenna is proposed with nonplanar director element as radiating elements. Throughout this paper, the design process of the proposed steerable phase array antenna for 8-12 GHz sensing application has been demonstrated in details.

Millimeter-wave couraggated surface for mutual coupling reduction between dipole antennas

The mutual coupling reduction between mm-wave dipole antennas using a corrugated surface is presented. The corrugated surface has a bandgap along the propagation direction toward the adjacent antenna. The mutual coupling is reduced between 4 to 20 dB when the corrugated surface is placed between the antennas. Moreover, the proposed corrugated surface does not have significant impact on the antenna radiation pattern.

Free space mutual coupling reduction between two SIW antennas at millimeter-wave frequency

A low-mutual coupling MIMO antenna system is presented in this paper. A cavity backed SIW antenna is designed to work at the millimeter-wave frequency at first. Then two elements of the designed antenna were integrated to achieve an MIMO system. In order to reduce the free space radiation mutual coupling, an AMC wall was inserted between two antennas. In order to design an AMC wall, a unit cell was simulated with periodic boundary condition. Scattering parameters show that a better isolation of -30 dB is achieved by using the AMC wall. Good isolation, radiation efficiency, and gain make the proposed antenna a good candidate for 5G frequency band.

Reconfigurable metamaterial unit-cell with controllable refractive index

In this paper a new reconfigurable metamaterial unit-cell is presented. The unit-cell has two PIN-diodes and operates in the frequency range of 1-4 GHz. Four different configurations can be achieved by switching the diodes that provides a maximum difference of 2 in the value of the unit-cells refractive index. This unit-cell can be used in advanced reconfigurable antenna applications.

Anisotropic metamaterial unit-cell for millimeter-wave applications

An anisotropic metamaterial unit-cell is designed and simulated operating at the frequency range of 30-35 GHz. This unit-cell provides two different effective refractive indexes depending on the direction of the incident wave. This feature is potentially useful for metamaterial-based beam-switching antenna techniques.

Towards Millimeter-wavelength: Transmission-Mode Fresnel-Zone Plate Lens Antennas using Plastic Material Porosity Control in Homogeneous Medium

We present two transmission-mode dielectric Fresnel-Zone Plate Lens (FZPL) antennas for use within the V-band spectrum. The proposed FZPs are realized via pure plastic material using two different additive manufacturing processes. The proposed FZP lenses are designed with half (λ/2) and quarter (λ/4) phase correction rings at 60-GHz with 30λ0 diameter, where λ0 is the free-space wavelength. The permittivity effect for lens sub-zones is controlled by material porosity in cube-shaped structures. The 3D printed zone plate lenses are built using additive manufacturing plastic materials with a thickness of λ0 and constant relative permittivities equal to 2.76 and 3.6. Different types of antenna with cosn-like radiation patterns as lens illuminators are analyzed on the vertical plane of the flat lenses to have a high efficiency over the considered operating band. Simulations and experimental measurements show a reasonably close match, therefore allowing for a reliable predictability.

8–12-GHz beam-shaping/steering phased antenna array system using SIW fed nonplanar director Yagi-Uda antenna

This paper presents a novel beam shaping/steering phase array system using substrate integrated waveguide (SIW) fed Yagi-Uda array antenna. This structure employs an integrated waveguide structure Lens as a beam shaping network (BSN). The proposed microwave lens is Rotman type integrated lens in substrate. A prototype phase array system is designed with 7 beam ports, 9 array ports, and 8 dummy ports. A 10 GHz SIW-fed Yagi-Uda antenna is proposed with nonplanar director element as radiating elements with scanning capability over (-24°, +24°). Throughout this paper, the design process of the proposed 8-12 GHz phase array system has been demonstrated in details.