This paper deals with the design and simulation of a Waveguide rotary joint using Gap Waveguide technology for millimeter wave applications. It contains two TE10 to TM01 mode converters and rotary junction between two circular Waveguides. The excited mode along the circular Waveguide for rotational symmetry purpose is TM01. The most important advantage of using Gap Waveguide technology is its ability to decrease complexity and cost of fabrication especially in millimeter wave frequencies because there is no requirement of contact between the different parts of the rotary joint structure. The Simulation results show that at different rotation angles the insertion and return loss are better than 0. 4 dB and 10 dB over 58. 5 GHz to 61 GH frequency band.

In this paper we present a one-dimensional monopulse antenna in groove Gap Waveguide (GGW) technology. A riblet coupler with a 90 degree delay line is designed to achieve proper sum and difference performances of the monopulse comparator. The outputs of designed 180 degree hybrid are connected to 4 way power dividers in order to feed the radiating elements. A 1×8 array of slots is used as the radiating section of the proposed antenna. A sample antenna is designed and simulated for operation at Ku band. Simulation results show that the return loss is more than 10 dB around 14GHz center frequency and the proper sum and difference performances.

In this paper a cavity backed slot antenna (CBSA) has been designed and fabricated in ridge Gap Waveguide technology. To increase the bandwidth of cavity backed slot antenna, two perturbations have been made at to corners of the RGW cavity. The perturbations cause to deviation of resonance frequencies of two degenerate TM100 and TM010 modes. The slot is embedded at the optimum place on the top plate of RGW cavity to create the radiation performance. The cavity is fed by a RGW which has been connected to WR62 Waveguide port via staircase transition. parametric study is done to obtain optimum dimensions and position of slot, perturbation and transition using HFSS software. The simulation results show about 10 % bandwidth for S11.

This paper presents a Butler matrix in Ridge Gap Waveguide (RGW)technology. For this purpose, we first design the riblet coupler in the millimeter wave band. The riblet coupler is designed with a coupling coefficient of 3 dB and a phase difference of 90 degrees at the outputs. Also, the return loss of all ports of this coupler in the frequency range of 53-60 GHz is better than 10 dB. Then we design a crossover and 45-degree phase shifter in the mentioned frequency range. By integrating four ribelt couplers, two phase shifters and a crossover, the Butler matrix structure is formed. The designed Butler matrix has 4 input and 4 output ports. The simulasion results of the designed matrix obtained by HFSS software show that for excitation of each input port in the frequency range of 53-60 GHz, the power is divided approximately equal between 4 output ports with a ratio of about -6 dB. But there is a linear phase difference between the matrix output ports, which also the phase of output ports change as the excitation port changes to other port. The simulation results are valid due to the desired amplitude and phase distribution at the matrix outputs. Also, comparing the results with those obtained by CST software confirms the proper performance of the designed matrix..

In this research paper, an innovative approach is employed to design and simulate a Bethe hole coupler utilizing ridge Gap Waveguide (RGW) technology. The RGW structure includes two parallel metal plates, a ridge, and strategically placed pins. To achieve the coupler structure, we place two Waveguides facing each other, and between these two Waveguides, there is a perforated metal plate. Initially, four holes are set in the plate between the Waveguides to enhance the coupling coefficient's bandwidth. The radius of the holes is initially calculated and designed to achieve a 20 dB coupling. The validity of the design is confirmed using CST software. RGW transition design is usually more difficult than other Gap Waveguide structures. For this reason, in this paper, a technique called Step Ridge Waveguide Excitation (SRWE) is introduced for efficient excitation of the designed coupler. The proposed methodology is implemented in the Ku band, which is suitable for satellite communication with high bandwidth. The dimensions of our structure are 50mm × 30mm × 17mm. Additionally, a 20±2 dB coupling coefficient is obtained for a fractional bandwidth (FBW) of approximately 29%. It demonstrates a directivity range of 6-16 dB, and the isolation is lower than 23 dB, surpassing the performance of similar previous works.

This paper presents a single layer circularly polarized (CP) antenna array based on Gap Waveguide (GW) technology for automotive radar applications. The antenna element is a curved slot that is cut into the top wall of a groove Gap Waveguide (GGW) structure. An 8×8 slot array antenna is constructed by combining eight sub-arrays of linearly arranged slots, using an 8-way power divider as the feeding network. The power divider and the transition from WR12 to GGW are also designed based on GW technology. The proposed antenna array operates in the frequency band from 76 GHz to 81 GHz, covering the automotive radar working bandwidth. The antenna has a maximum gain of 23. 8 dBi and a minimum axial ratio of 0. 5 dB. The antenna performance is verified by simulation using CST Microwave Studio.

recently a new structure called groove Gap Waveguide (GGW) i s introduced to implement low loss microwave component devices especi ally for millimeter wave applications. This paper presents a new type of H-plane horn antenna making use of this new technology in which back ward radiation is significantly suppressed by introducing a high impeda nce surface at the antenna aperture. The high impedance surface that w e used as the back lobe suppressor is a corrugated surface. The designed antenna is simulated by HFSS and its radiation performance is compar ed with an ordinary GGW H-plane horn in which no back lobe suppression mechanism is used. Results show a significant improvement in back lobe suppression and gain enhancement by the proposed structure.

This paper presents the design of a high-isolation power divider based on the groove Gap Waveguide. The proposed structure is similar to a rectangular Waveguide Magic-T when its difference port is terminated using a Waveguide match-load. Wideband impedance matching and high-isolation of the structure are obtained by placing some PEC steped cones inside the structure. First, a 1×2-way power divider is designed such that by combining a specific number of it, power dividers with more outputs can be acheived and to demonstrate this idea a 1×4-way power divider is assembled. The results of simulating the proposed power divider show that the structure has 33% frequency bandwidth covering from 42 GHz to 59 GHz. The structure reflection coefficient is below-15 dB, the insertion loss is lower than 0. 12 dB and the isolation is better than 18 dB in the whole frequency bandwidth and the simulation results prove that the proposed power divider is an excellent candidate for millimeter-wave applications.

Array antennas have many applications in civil and military systems such as: radar, surveillance systems, direction finders, electronic warfare (EW), etc. Feed network is one of the main parts of array antennas. In this paper a 1: 8 corporate feed network based on the new Waveguide technology referred to as ridge Gap Waveguide (RGW) at Ku band is designed and simulated which can be extended to any arbitrary 1: N feed network. The main advantages of RGW technology are: low loss, broad bandwidth, low sensitivity to manufacturing errors, usability at high frequencies like millimeter waves, easy integration of active components, etc. Return loss of the simulated feed network is better than-15 dB at 15-18 GHz frequency band. Furthermore, the insertion loss from the input to each output is almost-9dB which is as expected, and also the change of phase difference from input to each output is less than 1 degree.

In this paper, a millimeter-wave power divider based on Gap Waveguide technology is designed for use in the feeding network of a slot array antenna. The simulation results demonstrate that the proposed structure has about 10% matching input bandwidth in the 58-64 GHz frequency range. The significant advantage of using Gap Waveguide technology is that there is no requirement of good electrical contact among different metallic parts of the low-loss structure which considerably simplifies the manufacturing processes and mechanical assembly at millimeter-waves applications. Finally, a planar slot array antenna is designed with sidelobe level of-23 dB and bandwidth of 4. 1% at the center frequency of 60 GHz. The gain of antenna is higher than 21. 7 dB over the operation bandwidth from 58. 8 to 61. 25 GHz, corresponding to efficiency larger than 88%.