Design and Validation of Microstrip Gap Waveguides and Their Transitions to Rectangular Waveguide, for Millimeter-Wave Applications

The paper describes the design methodology, experimental validation and practical considerations of two millimeterwave wideband vertical transitions from two gap waveguide versions (inverted microstrip gap waveguide, and microstrip packaged by using gap waveguide) to standard WR-15 rectangular waveguide. The experimental results show S11 smaller than -10 dB over relative bandwidths larger than 25% and 26.6% when Rogers RO3003 and RO4003 materials are used respectively. The vertical transition from standard microstrip line packaged by a lid of pins to WR-15, shows measured return loss better than 15 dB over 13.8% relative bandwidth. The new transitions can be used as interfaces between gap waveguide feed-networks for 60 GHz antenna systems, testing equipment (like Vector Network Analyzers) and components with WR-15 ports, such as transmitting/receiving amplifiers. Moreover, the paper documents the losses of different gap waveguide prototypes compared to unpackaged microstrip line and Substrate Integrated Waveguide (SIW). This investigation shows that in V-band the lowest losses are achieved with inverted microstrip gap waveguide

Study of Dielectric Loss and Conductor Loss among Microstrip, covered Microstrip and inverted Microstrip Gap Waveguide utilizing variational Method in Millimeter Waves

In this paper,the classic variational method is applied for newly introduced inverted microstrip gapwaveguide.Then,the dielectric losses and the conductor losses among the microstrip, covered microstrip and inverted microstrip gap waveguide are analytically calculated based on the variational method in millimeter waves. According to our theory, the dielectric losses of microstrip and covered microstrip gap waveguide are at least 7 times higher than that of inverted microstrip gap waveguide. Therefore, inverted microstrip gap waveguide has huge advantage of low loss in millimeter waves

Research study of some RAM antennas Final report, 18 Nov. 1964 - 18 Jun. 1965

Input impedance and radiation pattern determinations for cylindrical gap, waveguide excited and circular waveguide slot antenna array

Towards an Advanced Automotive Radar Front-end Based on Gap Waveguide Technology

This thesis presents the early works on dual circularly polarized array antenna based on gap waveguide, also microstrip-to-waveguide transitions for integration of automotive radar front-end. Being the most widely used radar antenna, PCB antenna suffers from dielectric loss and design flexibility. Next generation automotive radars demand sophisticated antenna systems with high efficiency, which makes waveguide antenna become a better candidate. Over the last few years, gap waveguide has shown advantages for implementation of complicated antenna systems. Ridge gap waveguides have been widely used in passive gap waveguide components design including slot arrays. In this regard, two transitions between ridge gap waveguides and microstrip lines are presented for the integration with gap waveguide antennas. The transitions are verified in both passive and active configuration. Another work on packaging techniques is presented for integration with inverted microstrip gap waveguide antennas.Systems utilizing individual linear polarization (LP) that lack polarimetric capabilities are not capable of measuring the full scattering matrix, thus losing information about the scenery. To develop a more advanced radar system with better detectability, dual circularly polarized gap waveguide slot arrays for polarimetric radar sensing are investigated. An 8 78 planar array using double grooved circular waveguide polarizer is presented. The polarizers are compact in size and have excellent polarization properties. Multi-layer design of the array antenna benefits from the gap waveguide technology and features better performance. The works presented in this thesis laid the foundation of future works regarding integration of the radar front end. More works on prototyping radar systems using gap waveguide technology will be presented in future publications

Design of a coplanar waveguide-to-ridge gap waveguide transition via capacitive coupling

A transition from Coplanar Waveguide (CPW) via capacitive coupling in order to provide feeding to the so-called Ridge Gap Waveguide (RGW) has been investigated. The main objective of this work is to find a way to facilitate integration of active electronics with the gap waveguide structure and also to do measurements of the components made in gap waveguide technology working around 100 GHz. The transition design and simulation of S parameters for the designed topology is presented

E-band One-step 45 Double wing Gap Waveguide Twist for Waveguide WR12

This paper presents a novel double-wing one-step 45 degrees Gap waveguide twist at E-band. By employing an optimal double-wing structure for Gap waveguide flange, only one gap waveguide section is needed for the polarization transform between diagonal polarization and horizontal/vertical polarization, which does not require good conductive contacts between the connected flanges. This new waveguide twist is in particular useful and of low cost at millimeter wave frequency and up to THz

Design of Wideband Slot Array Antenna by Groove Gap Waveguide in Millimeter Waves

The newly introduced gap waveguide technology offers non-contact waveguide configurations so that the good electrical contact between different metallic layers can be avoided. Thereby, the gap waveguide structures are relatively simple to manufacture, especially at millimeter and sub-millimeter wave frequencies. This work systematically presents a high-efficiency corporate-fed slot array antenna based on groove gap waveguide in the millimeter waves. A cavity-backed slot sub-array is firstly designed in a groove gap waveguide cavity. The cavity is fed through a coupling hole from groove gap waveguide distribution network at the bottom layer. The sub-array is numerically optimized in an infinite array environment. Low side lobes are obtained in the both E- and H-planes by diagonal placement of the radiation slot rotating by 45 degrees. Furthermore, the radiation narrow slot pair is adopted so that the good cross polarization is achieved. The fabricated antenna depicts more than 25% bandwidth with input reflection coefficient better than -8 dB and the aperture efficiency higher than 60% with around 25 dBi realized gain between 70 and 90 GHz. The measured cross polarization level is below -27 dB, which satisfies the ETSI standard

Fast analysis of gap waveguides using the characteristic basis function method and the parallel-plate Green’s function

The Characteristic Basis Function Method is employed in conjunction with the parallel-plate dyadic Green's function method to obtain the impedance characteristics of electrically large gap-waveguide structures. Numerical results are shown for the groove gap waveguide demonstrating reduced execution times relative to the HFSS software, while the solution accuracy is barely compromised

Investigation of Transitions for Use in Inverted Microstrip Gap Waveguide Antenna Arrays

The main purpose of this work is to create good transitions for inverted microstrip-based versions of gap waveguide that are used to feed slot or horn antenna arrays. Two new millimeter-wave transitions from inverted microstrip gap waveguide to rectangular waveguide are presented. Both geometries are similar and consist of a planar probe, which contains a rectangular patch or T-section. The planar probe is inserted inside the rectangular waveguide through an opening made in the broadside wall of the waveguide. The main difference between the two geometries is that one of them extends upwards and the other one downwards with respect to the planar inverted microstrip gap waveguide circuit. The simulated S-parameters show promising results

Coupling of nitrogen-vacancy centers in diamond to a GaP waveguide

The optical coupling of guided modes in a GaP waveguide to nitrogen-vacancy (NV) centers in diamond is demonstrated. The electric field penetration into diamond and the loss of the guided mode are measured. The results indicate that the GaP-diamond system could be useful for realizing coupled microcavity-NV devices for quantum information processing in diamond.Comment: 4 pages 4 figure