Study of Grating Efficiency of Planar Arrays

This paper studies the aperture efficiency reduction due to grating lobes of a uniformly excited planar array. The grating lobes will not cause major interference problems in the millimeter wave region, because of the attenuation in the atmosphere, but they cause a reduction of the directivity and thereby aperture efficiency of the antenna. Therefore, we present a simple formula for calculating the aperture efficiency in the presence of grating lobes, from knowledge of the element pattern. The accuracy of the formula is verified by comparing with simulated results for a full array with slot elements

High Efficiency 2x2 Cavity-Backed Slot Sub-array for 60 GHz Planar Array Antenna Based on Gap Technology

This paper presents a two layer 2x2-slot element as a sub-array for 60 GHz planar array antenna based on gap waveguide technology. The proposed element consists of 2x2 slots in a gap waveguide cavity where the cavity is fed through a coupling slot from a ridge gap waveguide corporate-feed network in a lower layer. The 2x2-slot sub-array is numerically optimized in an infinite array environment. The designed sub-array shows the relative bandwidth of 11% with reflection coefficient better than -13 dB over 58.2-65 GHz frequency band. A prototype of a 8x8-element slot array antenna is designed and fabricated in order to verify the simulations

V-band high efficiency corporate-fed 8×8 slot array antenna with ETSI class II radiation pattern based on gap technology

A multilayer gap waveguide 8×8 slot array antenna with high efficiency for 60 GHz applications is presented in this paper. The proposed antenna is composed of three unconnected metal layers. A ridge gap waveguide corporate distribution network feeds a radiation layer with 4×4 cavity-backed slot subarrays. The co-polar radiation pattern and sidelobe levels of the antenna are improved by using a simple slot-tilting method to fulfill the radiation pattern requirement of the ETSI 302 standard for fixed radio links. The fabricated prototype has a relative bandwidth of 12 % with input reflection coefficient better than -10 dB. The E- and H-planes radiation patterns satisfy the ETSI class II co-polar sidelobe envelope over 57-65 GHz frequency band. The measured total aperture efficiency is better than 65% over the operating frequency band

Compact RF Integration and Packaging Solutions Based on Metasurfaces for Millimeter-Wave Applications

The millimeter-wave frequency range has got a lot of attention over the past few years because it contains unused frequency spectrum resources that are suitable for delivering Gbit/s end-user access in areas with high user density. Due to the limited output power that the current RF active components can deliver in millimeter-wave frequencies, antennas with the features of low profile, high gain, high efficiency and low cost are needed to compensate free space path loss and increase the communication distance for the emerging high data rate wireless systems. Moreover, it is desired to have a compact system by integration of the antenna with passive and active components at high frequencies.In order to move towards millimeter-wave frequencies we need to face significant hardware challenges, such as active and passive components integration, packaging problems, and cost-effective manufacturing techniques. The gap waveguide technology shows interesting characteristics as a new waveguide structure. The main goal of this thesis is to demonstrate the advantages of gap waveguide technology as an alternative to the traditional guiding structures to overcome the problem of good electrical contact due to mechanical assembly with low loss. This thesis mainly focuses on high-gain planar array antenna design, integration with passive and active components, and packaging based on gap waveguide technology. \ua0We introduce several low-profile multilayer corporate-fed slot array antennas with high gain, high efficiency and wide impedance bandwidth operating at the millimeter-wave frequency band. A system demonstration consisting of two compact integrated antenna-diplexer and Tx/Rx MMICs for Frequency-division duplex (FDD) low latency wireless backhaul links at E-band is presented to show the advantages of gap waveguide technology in building a complete radio front-end. Moreover, the use of several new manufacturing methods, such as die-sink Electric Discharge Machining (EDM), direct metal 3-D printing, and micro-molding are evaluated to fabricate gap waveguide components in a more effective way.Furthermore, a novel air-filled transmission line, so-called multi-layer waveguide (MLW), that exhibits great advantages such as low-cost, simple fabrication, and low loss, even for frequencies beyond 100 GHz, is presented for the first time. To constitute an MLW structure, a rectangular waveguide transmission line is formed by stacking several thin metal layers without any electrical and galvanic contact requirement among the layers. The proposed concept could become a suitable approach to design millimeter-wave high-performance passive waveguide components, and to be used in active and passive components integration ensuring mass production at the same time

High gain V-band planar array antenna using half-height pin gap waveguide

With growing demand for mm-Wave applications, gap waveguide technology introduced many advantageous features compared to hollow waveguides or SIW. Till now several wideband, high-efficiency and highly directive planar gap waveguide antennas have been proposed. Recently, a new form of pins, the so called half-height pin, is proposed for realizing gap waveguide technology. In this paper, a wide-band, high gain, and high efficiency 8 78-element slot array antenna for 60 GHz band based on the new form of pins is introduced. The simulation shows a very good performance of the antenna, with 14% bandwidth of the 10 dB return loss, 26 dBi realized gain and close to 80% aperture efficiency. The antenna has less difficulty in manufacturing because of new pin form and therefore is suitable for the low cost mass production of mm-Wave antennas

A multi-layer gap waveguide array antenna suitable for manufactured by die-sink EDM

In this paper, a multilayer wideband slot array antenna is presented for high gain applications at V-band. The proposed antenna consists of three unconnected metal layers based on the recently introduced gap waveguide technology. A 2×2 cavity-backed slot subarray is fed by a ridge gap waveguide corporate distribution network. The subarray is optimized to have wide bandwidth and low grating lobes in an infinite array environment. A simple slot-tilting method is used to fulfill the radiation pattern requirement of the ETSI 302 standard for fixed radio links. A prototype consisting of 16×16 slots is manufactured by die-sink Electric Discharge Machining (EDM), a fast modern planar-3D spark machining method. The measured antenna has a relative bandwidth of 18% with input reflection coefficient better than -10 dB, and the radiation patterns satisfy the ETSI 302 standard co-polar sidelobe envelope over 56-67 GHz frequency band. The measured total aperture efficiency is over most of the frequency band better than 80%

Substrateless Packaging for a D-Band MMIC Based on a Waveguide with a Glide-Symmetric EBG Hole Configuration

This paper presents a novel substrateless packaging solution for the D-band active e mixer MMIC module, using a waveguide line with a glide-symmetric periodic electromagnetic bandgap (EBG) hole configuration. The proposed packaging concept has the benefit of being able to control signal propagation behavior by using a cost-effective EBG hole configuration for millimeter-wave- and terahertz (THz)-frequency-band applications. Moreover, the mixer MMIC is connected to the proposed hollow rectangular waveguide line via a novel wire-bond wideband transition without using any intermediate substrate. A simple periodical nail structure is utilized to suppress the unwanted modes in the transition. Additionally, the presented solution does not impose any limitations on the chip\u27s dimensions or shape. The packaged mixer module shows a return loss lower than 10 dB for LO (70-85 GHz) and RF (150-170 GHz) ports, achieving a better performance than that of traditional waveguide transitions. The module could be used as a transmitter or receiver, and the conversion loss shows good agreement in multiple samples. The proposed packaging solution has the advantages of satisfactory frequency performance, broadband adaptability, low production costs, and excellent repeatability for millimeter-wave- and THz-band systems, which would facilitate the commercialization of millimeter-wave and THz products

Design of 8 7 8 Slot Array Antenna based on Inverted Microstrip Gap Waveguide

In this paper we present the design of a high efficiency corporate-fed 8 7 8 slots array antenna in the 60-GHz band. The antenna is built using four unconnected layers — bed of nails, which works as Artificial Magnetic Conductor (AMC), PCB microstrip feeding networks, groove waveguide cavity and radiation slots layer on the top. The designed antenna shows a relative bandwidth of 14.63% with input reflection coefficient better than -15 dB and an overall efficiency larger than 70% with about 26.5 dBi simulated gain between 57 and 66 GHz

Design of integrated diplexer-power divider

A new configuration is introduced to integrate diplexers and power dividers. The proposed configuration is based on coupling matrix. The design of the lumped element network is based on addition of an extra term to the conventional error function of the coupling matrix to decouple the two ports of the power divider. An optimized lumped element network is implemented successfully on an EBG based guiding technology known as ridge gap waveguide. The optimization of the physical structure is done efficiently by dividing the diplexer-power divider into many sub-circuits and analyzing the corrected delay response of them