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This study presents the design of a low‐cost fractal antenna loaded with parasitic edge‐coupled (EC) split ring resonators (SRR). Parasitic EC SRR elements result in improved impedance matching leading to improved bandwidth. The basic resonant structure is a circular patch antenna designed at 3.2 GHz on low‐cost FR4 substrate with relative permittivity 4.4, and 1.6 mm thickness. A single iteration of circular patch and slots is used to make it fractal and in order to achieve multiband performance, the antenna is inset fed by a 50 Ω microstrip line. A prototype of the proposed antenna is fabricated and tested for results, a comparison between fractal antenna with and without SRRs is made and the results confirm that a better impedance matching is achieved in the later case, also a 3% increase in bandwidth is achieved at 8.5 GHz. A good agreement between simulated and measured results is obtained, an estimated gain of 13.3 dB is provided by the proposed antenna. The overall dimensions of the antenna are 45 mm × 45 mm and it may be used for wireless applications at 3, 5, 6.8, 7.5 and 8.5 GHz with an average bandwidth of 200 MHz.

This paper presents a hybrid design of Sierpinski Carpet and Minkowski antenna for wireless applications. The hybrid antenna is designed, simulated and fabricated on an FR4 substrate with thickness 1.6 mm and dielectric constant 4.4. The dimensions of antenna are 45 × 38.92 × 1.6 mm 3 which operates at various frequencies 3.43 GHz, 4.78 GHz, 6.32 GHz, 8.34 GHz and 9.64 GHz, and can be used for Wi-Max, C-band applications, Point-to-point Hi speed wireless communication and X-band (satellite Communication) applications. The measured results are also compared with the simulated ones which are in agreement with each other. Ansoft High Frequency Structure Simulator (HFSS) is used to design and simulate the antenna.

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This article demonstrates the design and development of WR-15 transition using an antipodal microstrip dipole antenna at a frequency of 60 GHz for space applications. An inline microstrip line to rectangular waveguide (MS-to-RWG) transition is proposed for the V-band (50–75 GHz) functioning. The RF energy is coupled and launched through an antipodal dipole microstrip antenna. Impedance matching and mode matching between the MS line and dipole are achieved by a quarter wave impedance transformer. This results in the better performance of transitions in terms of insertion loss (IL > −0.50 dB) and return loss (RL < −10 dB) for a 40.76% relative bandwidth from 55.57 GHz to 65.76 GHz. The lowest values of IL and RL at 60 GHz are −0.09 dB and −32.05 dB, respectively. A 50 μm thick double-sided etched InP substrate material is used for microstrip antipodal dipole antenna design. A back-to-back designed transition has IL > −0.70 dB and RL < −10 dB from 54.29 GHz to 64.07 GHz. The inline transition design is simple in structure, easy to fabricate, robust, compact, and economic; occupies less space because the transition size is exactly equal to the WR-15 length; and is prepared using an InP substrate with high permittivity of 12.4 and thickness of 50 μm. Thus, the devices have the lowest insertion loss value and lowest return loss (RL) value, of <−31 dB, as compared to earlier designs in the literature. Therefore, the proposed design has the lowest radiation loss (because of thickness) and highest transmission (about 97% power). Easy impedance matching using only a single-step quarter-wave transformer between the antipodal dipole antenna and 50 Ω microstrip line (avoiding the multi-sections’ demand and microstrip line’s tedious complexity) is needed. Since, when the InP dielectric substrate is inserted in WR-15, the waveguide becomes a dielectric-filled waveguide (DFWG), and its characteristics impedance reduces to 143 Ω from 505 Ω at an operating frequency of 60 GHz. In the proposed transition, no ridge waveguide or waveguide back-short is utilized in WR-15. The microstrip line did not contain any via, fence, window, screw, galvanic structure, post, etc. Hence, the transition is suitable for high-data-rate 5G communications, satellite remote sensing, missile navigation, MIC/MMIC circuits’ characterization, and mm-wave applications. The electrical equivalent model of the proposed design has been generated and validated using an RF circuit simulator and was found to have excellent matching.

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