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The letter presents a low‐windage omnidirectional antenna for high‐speed aircraft in the UHF and L bands. It combines a planar biconical antenna with a printed tape parasitic branch monopole antenna. Upgrading the traditional restricted‐length biconical antenna to a double‐layer planar design meets the compact, lightweight, and low windage requirements of airborne use. To enhance bandwidth and meet the lightweight, compact criteria of high‐speed aircraft, the planar‐printed monopole antenna integrates parasitic stubs and loop antenna concepts. Experimental results exhibit excellent isolation between antenna elements, with over 15 dB segregation and operational spectrum return loss of 27% and 18% at 10 dB. The voltage standing wave ratio is below 2, with less than 5 dB variation in the horizontal radiation pattern across frequency bands. The antenna, measuring 20 mm × 190 mm × 270 mm and weighing around 0.5 kg, holds great promise for high‐speed aircraft applications. [ABSTRACT FROM AUTHOR]

In this paper, a lightweight high-efficiency circularly polarized (CP) all-metal antenna design method is presented for satellite industry applications. The proposed antenna is composed of a rectangular waveguide feeder, a high-order mode cavity and a metasurface circular polarizer (MCP). The cavity high-order mode TE440 is directly excited by four coupling slots in the waveguide. The MCP is placed on the cavity to generate the CP radiation. Due to the introduction of high-order mode technology and MCP, all metal walls inside the antenna can be removed, which are necessary in conventional waveguide structures, and weight is thereby significantly reduced. To reflect the weight advantage, a conventional metal wall-loaded waveguide antenna of the same size is designed. The measured results show that the proposed antenna has wider impedance and axial ratio bandwidths, and higher radiation efficiency. In particular, the proposed antenna is 40% lighter than the comparative one, indicating that it is more applicable to satellite platforms with limited loading capacities. [ABSTRACT FROM AUTHOR]

A broadband asymmetric coplanar waveguide antenna is designed. In this design, two periodical composite right/left‐handed transmission line (CRLH‐TL) unit cells were chosen to generate three resonating modes. The broadband characteristic of this antenna can be achieved by combining the first‐negative‐order resonance, zeroth‐order resonance, and first‐positive‐order resonance of CRLH‐TL. A prototype structure of our proposed antenna has been fabricated and tested. The dimensions of the antenna are 30.0 × 40.0 × 1.6 mm3, which corresponds to 0.19 λ0 ${\lambda }_{0}$ × 0.25 λ0 ${\lambda }_{0}$ × 0.01 λ0 ${\lambda }_{0}$, where λ0 ${\lambda }_{0}$ is the free‐space wavelength at 1.88 GHz. The measured band in which S11 is below −10 dB ranges from 1.80 to 3.75 GHz with the fractional bandwidth of 70.27%. The radiation patterns of the proposed antenna are highly consistent throughout the operating band, which covers the band of WiMAX, with the measured average peak gain of 2.77 dBi and radiation efficiency of 86.63%. [ABSTRACT FROM AUTHOR]

This paper presents a low‐insert loss and high‐return loss bandpass filter (BPF). The proposed BPF consists of cut‐off rectangular waveguides and capacitive irises, showing an extremely low insert loss and a high return loss at 7.85‐8.5 GHz in the bandpass frequency range. The insert loss is less than 0.203 dB, the return loss is better than 30 dB and the attenuation exceeds 40 dB at 7.3 GHz and 9.05 GHz. Moreover, the fractional bandwidth of proposed BPF is 7.95%. The validity of the device was tested by comparison among experimental and simulation data; the results suggest that it is in satellite communication systems. [ABSTRACT FROM AUTHOR]

In this paper, a directional‐coupler‐based wideband three‐way waveguide power divider is demonstrated. The proposed power divider consists of tapered rectangular waveguide, six‐port directional coupler and iron pentacar‐bonyl terminations. Its fractional bandwidth is 10.99% at 12.9 to 14.4 GHz. In addition, the return loss of all input and output ports is better than 20 dB and the isolation of the three output ports is more than 20 dB. Moreover, the insert loss is better than 5.19 dB including the power division ratio of 4.8 dB and the amplitude imbalance among the three output ports of less than ±0.4 dB. The experimental results agree well with the simulation ones, which indicates the validity of our method. With the above‐mentioned characteristics, the proposed device can be widely used in Ku band communication systems. [ABSTRACT FROM AUTHOR]