A compact, wideband, low cost, high radiation efficiency and planar half mode Substrate Integrated Waveguide (HMSIW) horn antenna is proposed in this work. For the first time, HMSIW is used to design a horn antenna. By using HMSIW Waveguide structure instead of Substrate Integrated Waveguide (SIW), the impedance bandwidth of antenna is increased significantly. The use of this Waveguide structure in the design of the horn and its feeding system has increased the impedance bandwidth of the antenna. In fact, leaking the electromagnetic waves gradually along the horn increases the bandwidth of antenna. By applying the design equations of the H-plane horn antenna and half mode Substrate Integrated Waveguide, the initial dimensions of the antenna have been obtained, then the best possible solution has been extracted by parametric study and optimization. Simulation results exhibit an impedance bandwidth of 50% from 24GHz to 40GHz. Also, the proposed design shows a gain between 7dB and 10 dB together with radiation efficiency higher than 95% over the frequency band of 25 to 35GHz. The innovation of this work is in providing a new horn structure based on HMSIW with wide impedance bandwidth. In the previously presented works, which are mainly based on SIW, the antenna suffers from a narrow impedance bandwidth.

A new wideband Wilkinson Power Divider which use the nonuniform Substrate Integrated Waveguide (NSIW) method is presented in this paper. This structure utilizes NSIWs instead of the uniform quarter wavelength SIWs in conventional Wilkinson power divider. The proposed structure is analyzed by odd and even mode analysis. The proper NSIW section widths can be extracted by using even mode while the divider resistances are achieved by odd mode analysis. Moreover using of half mode structure in the NSIW and two output ports reduces the overall size of the proposed divider. Finally a wideband Wilkinson power divider is designed and simulated to verify the proposed design method. A good return loss (S11, S22) and insertion loss (S21) across a very wideband width from 10 GHz to 20 GHz is achieved. Also, the isolation (S23) is better than -10 dB from 9.5 GHz to 21.5 GHz for the designed NSIW divider.

This paper presents a filtering power divider (PD) /power combiner (PC) using Substrate Integrated Waveguide (SIW) -based 180o hybrid. The utilized 180o hybrid includes a standard H-plane 3-dB coupler and a broadband 90o phase shifter. The phase shifter is composed of non-radiating longitudinal slots patterned on the top conducting surface of the SIW. We have added the filtering property to the structure by an array of dissimilar transverse slots. The slots dimensions are obtained by the extracted external quality factor, coupling coefficient and the relationship between them and the slots dimensions. The proposed structure is designed for 8.2 GHz and investigated by ADS simulator. The results show the fractional bandwidth of the sum and difference ports are 13.7% and 14.93%, respectively. For sum operation, the minimum insertion loss is 3.78 dB and the return loss is above 25 dB in the passband. For difference operation, the minimum insertion loss is 3.81 dB and the return loss is above 26 dB in the passband.

In this pare, a wideband three-order bandpass filter (BPF) is proposed. The proposed wideband filter is designed using the Substrate Integrated Waveguide (SIW) structure by loading T-shape slots. A BPF with two resonators is formed by etching T-shape slots with different size on the top metal plane of the SIW structure. The proposed filter is investigated with the theory of coupled resonator circuits. The T-shape slots which etched on the SIW structure are used to form up a new multiple-mode resonator (MMR) in order to achieve a wide passband of operation while keeping the overall size of the proposed filter to be much compact. The design procedure as well as design curves of the filter are given and discussed here. Compared with some other reported BPFs with SIW technique, the presented BPF using the SIW structure loaded by T-shape slot has great improvements on size reduction and selectivity. In order to prove the validity, the proposed wideband SIW BPF on a single layer printed circuit board (PCB) is designed and experimentally examined. The measured results show that the filter achieves an insertion loss of 1. 1 dB at 6. 4 GHz and a return loss of higher than 22 dB. The proposed filter has a pass-band covers 5. 1 to 7. 99 GHz and its simulated and measured 3 dB fractional bandwidth is about 44. 3%. The measured results are in a good agreement with the simulated results.

A four-way power divider/power combiner using Substrate Integrated Waveguide (SIW) and microstrip lines is proposed and investigated. The proposed power divider consists of a double-layer Substrate with a bottom layer including an SIW T-junction and a top layer including a microstrip network. This microstrip network consists of a modified Gysel power divider which provides a high isolation between output ports by using two grounded resistors. Meanwhile, this modified Gysel power divider maintains high power-handling advantage over Wilkinson power divider. A transition between the SIW T-junction and microstrip network is realized by etching two rectangular slots on the middle metal layer. The even-odd mode method is used to analyze the presented structure. A prototype of the proposed power divider is designed, simulated, and fabricated. The results show that the return loss of the input port is better than 12 dB over 8. 43 to 10. 57GHz. Also, the output return losses and isolation are better than 10. 5 dB over the whole bandwidth.

circularly-polarized antenna is built based on new SIW(Substrate Integrated Waveguide) structure which contains cavity-backed resonator and a conventional polarized ring with two square slits in inner and outer ring that differ 90° at position and is proposed for right-handed circular polarization (RHCP) and fabricated in two separate layers. A broadband impedance bandwidth of 13.9% and a RHCP axial ratio of 0.5GHz have been obtained under the condition of less than VSWR ≤2 and axial ratio≤ 3 dB, respectively.