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In this letter, a novel frequency-independent circular polarized antenna is proposed for satellite communication application. It consists of a slot coupled antenna and a planar metasurface. Four compact sequential L-shaped feeding lines could generate energy to the metasurface through the metallic ground embedded cross slot. Therefore, surface waves could propagate on the metasurface, making the antenna generate additional resonances. Then, wide impedance bandwidth and axial ratio bandwidth of the proposed antenna can be achieved. Besides, the proposed antenna has low profile (0.05 λ 0 at 3.5 GHz), frequency independent, large front-to-back ratio, high gain, and wide half-power beamwidth property. It has great potential in global satellite communication systems and satellite navigation systems (S band and C band).

In this paper, a compact broadband bandpass filter (BPF) using triple-mode stepped-impedance stub-loaded resonator (TMSISLR) is proposed. The TMSISLR is composed of an impedance-transforming unit and two asymmetrical open-ended stepped-impedance stubs (SIS) at the center. By simply adjusting the impedances of the SIS, the resonant frequencies of the TMSISLR can be flexibly changed. The interdigital coupled-lines are adopted to feed the proposed TMSISLR. This BPF can realize wide bandwidth, low insertion loss, high selectivity, and deep stopband rejection simultaneously. Finally, the proposed BPF is simulated, fabricated, and measured. The measured results show that the impedance bandwidth under −16.7 dB is 86% from 1.89 to 4.75 GHz, while the insertion loss is smaller than 1.47 dB. The measured insertion loss is larger than 30 dB at both low- and upper-stopband (from 0 to 1.27 GHz and 6.03 to 7.66 GHz). The measured results are in good agreement with the simulated counterpart.