Abstract: This paper presents a new method for designing a dual-frequency patch antenna with circular and linear polarizations. Dual-frequency operations are behaved by etching two narrow slots close to the radiating edges of a rectangular patch. The circular polarization at the lower resonant frequency of the dual-frequency antenna can be achieved by setting a perturbation segment at an appropriate location in the patch element, and placing the feed point on the diagonal axis. Several experimental results of a designed antenna show the good characteristics for circular and linear polarizations at both resonant frequencies.
CLC number：TN821.1 Document code： A
Key words: dual-frequency; slot patch antennas; linear polarization; circular polarization
In radar and communication systems, dual-frequency operations are often required. Specially, in modern mobile global position system (GPS), it will be desirable that one of two frequencies is the circular polarization. Planar antenna has been investigated for multi-frequency very well since it is advantageous in low cost, low weight and conform ability. Early dual-frequency planar antenna is multilayered stacked-patch structure, and the radiating element is used to be circular[1], annular[2], rectangular[3]and triangular patches[4]. Recently, a dual-frequency antenna is introduced in which the structure is dingle layer patch with two slots close to the radiating edges, and good performances of simultaneous impedance matching and gain are demonstrated for both resonant frequencies. However, all the conventional investigations are only for the case in which the antenna polarization is linear, while the dual-frequency antenna with circular polarization has not been touched yet.
摘 要：提出了一種同時具有圓極化和線極化的雙頻新型開槽微帶天線的設(shè)計方法。天線雙頻工作是通過分別在靠近方形微帶天線的兩個輻射邊處各開一個平行的窄槽來實現(xiàn)的。在較低的諧振頻率處圓極化的可以通過在天線輻射單元上適當?shù)卦O(shè)置攝動元素，并將饋電點移到輻射單元的對角線上。一個設(shè)計天線的測試結(jié)果給出了該天線在兩個諧振頻率上具有很好的圓極化和線極化的天線性能。
關(guān)鍵詞：雙頻；開槽微帶天線；線性極化；圓極化
在雷達和通信系統(tǒng)中，經(jīng)常需要雙頻工作。特別是在現(xiàn)代的移動全球定位系統(tǒng)中，通常要求雙頻之一為圓極化。因為平面天線在低成本、重量輕和穩(wěn)定性方面的優(yōu)點，已經(jīng)被廣泛研究并較好的應用于多頻帶系統(tǒng)中。早期的雙頻平面天線是多層棧式貼片結(jié)構(gòu)，它的輻射單元習慣上為圓形、環(huán)形、矩形和三角形。最近，提出了一種雙頻天線，這種天線的結(jié)構(gòu)是單層貼片，且有兩個槽靠近輻射邊緣，并且在兩個諧振頻率上既實現(xiàn)阻抗匹配又具有好的增益性能。然而，常規(guī)的研究僅僅針對線性極化的天線，擁有圓極化的雙頻天線卻還沒有被實現(xiàn)。