A low-profile wideband conical beam antenna which uses two concentric annular ring slots in substrate integrated waveguide (SIW) technology is presented. First, a single ring antenna is considered and then the effect of introducing the second slot on bandwidth is investigated and high bandwidth is achieved. A brief parametric study for different slot width is presented. A prototype of the proposed antenna is fabricated and measured. The measured reflection coefficient is in good agreement with simulation. The theoretical result is also provided for S11 to validate the simulation and measurement results. The proposed antenna shows 30% bandwidth in 17 GHz center frequency (|S11<-10 dB). Radiation pattern was measured in three different frequencies in the entire frequency bandwidth. Maximum measured radiation efficiency is 93%. The antenna is very simple and low profile with a planar structure. Electrical dimensions are (1. 76𝜆 𝜆 0×1. 76𝜆 𝜆 0×0. 08𝜆 𝜆 0) with very simple feeding network which could be a suitable choice in many practical applications from anti-collision radars to WLAN applications.

In this paper, a compact 6. 8/7. 6 GHz diplexer is provided with the help of substrate integrated waveguide (SIW) structures. The use of this structure is for satellite communication systems. The designed diplexer includes a T-junction. In addition, our structure consists of two SIW filters of the type of bandpass. The relative bandwidth of the upper channel is 3. 3% at the center frequency of 7. 6 GHz and its lower channel is 3. 7% at the center frequency of 6. 8 GHz. The proposed diplexer offers a great benefit in terms of size decrease. In addition, it displays an optimal insertion loss. While giving the low return loss. Ultimately, the designed structure displays ideal rates of isolation and rejection. The diplexer incorporates a planar form and can be simply integrated with to the integrated circuits of the microwave. The insertion and return losses are 1. 8 dB and 15d B in the lower band and they are 1. 9 dB and 17 dB in the upper band. Simulations have been implemented with CST Microwave Studio. The Diplexer is completely built into a standard printed circuit board (PCB) procedure. A very favorable compromise is reached among the results of the construction and the measurement, which is the evidence of the proposed method.

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.

The demand for mobile communication systems with high data rate has drawn attention to the millimeter-wave frequencies to increases the channel capacity compared to current 4G cellular networks. So, the fifth generation (5G) mobile communications is presented which is to work in mm-wave frequency band to improve data rate, capacity and latency. One of the challenges of 5G application is the base station and mobile antennas which should be robust against fading. Therefore, in this paper, a two port substrate integrated waveguide (SIW) slot base station antenna for 5G application at 28 GHz is presented. The realized gain of the two-port antenna with a high isolation (20 dB) and circular polarization is 6. 35 dBi. The 5-element array of the two-port antenna with the same excitation can increase the gain 8 dB, but it has some nulls. With phase shift for excitation ports, the nulls are cancelled.

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.