| Summary: | 碩士 === 逢甲大學 === 電機工程學系 === 106 === Recently, it is a prerequisite requirement for hand-held communication products to possess the advantages such as light in weight, compact size and low manufacturing cost. To satisfy these requirements, a single structure design that comprised of an antenna integrated with the front-end circuit of the communication system is presently attracting many attentions. However, high order harmonic modes excited by the antenna can cause electromagnetic interference (EMI) problems on the active circuit, which lead to degrading the performances of the system. Hence, the common solution to solve this problem is to use low-pass or band-pass filter. However, this method will increase the circuit size, manufacture cost, and insertion loss. To resolve these disadvantages, antenna design with harmonic suppression is now an attractive topic of research interest.
This thesis is divided into two parts, the first part presents a wide band harmonic suppression circular ring slot antenna that operate in the 2.45 GHz wireless local area network (WLAN) band. Here, a novel stepped impedance resonator (SIR) structure as a low-pass filter and the open stubs (OS) as a band-stop filter are integrated into the circular ring slot antenna, so that it can suppress unwanted high order harmonic modes (return losses < 3 dB) within the frequencies range from 3 to 20 GHz. Also, it is well known the conventional ring slot antenna is a half wavelength resonator whereas the SIR structure is not only regarded a LPF but also can reduce the size of antenna about 15 % by its electrical characteristic.
In the second part of this thesis, a triple-band circular ring slot antenna with wideband harmonic suppression is proposed. It is noteworthy that this triple-band circular ring slot antenna with wideband harmonic suppression design has no effect on the fundamental resonate mode with etching extra slots, so that can operate in the 2.4 GHz, 5.2 GHz and 5.8 GHz WLAN application.
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