使用鐵電可變電容之頻率可調微帶貼片天線;Frequency-Reconfigurable Microstrip Patch Antennas Using Ferroelectric Varactors

NCUIR > College of Electrical Engineering & Computer Science > Graduate Institute of Electrical Engineering > Electronic Thesis & Dissertation > Item 987654321/73027

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/73027

Title:	使用鐵電可變電容之頻率可調微帶貼片天線;Frequency-Reconfigurable Microstrip Patch Antennas Using Ferroelectric Varactors
Authors:	陳贈元;Chen, Tseng-Yuan
Contributors:	電機工程學系
Keywords:	天線;Antenna
Date:	2017-01-20
Issue Date:	2017-05-05 17:39:23 (UTC+8)
Publisher:	國立中央大學
Abstract:	在天線中加入可調元件可達到操作頻率可調的效果。在本論文中，我們負載可變電容於微帶貼片天線，使其頻率可調。我們設計並製作兩種頻率可調微帶貼片天線；此二天線皆使用以鈦酸鍶鋇為介電質的鐵電可變電容作為其電容負載。其中一個微帶貼片天線以苯並環丁烯（BCB）為介電質，而另一個則是以高電阻率矽基板為介電質。以BCB為介電質的天線，操作頻率設計於15 GHz附近。我們使用本實驗室所發展的BCB堆疊貫孔製程來連接貼片天線與鐵電可變電容。量測結果顯示，當可變電容的偏壓從0 V調至25 V時，天線操作頻率從13.8 GHz變化到14.3 GHz，換算出的頻率可調範圍為3.5%。以高電阻率矽基板為介電質的天線，操作頻率亦設計在15 GHz附近。我們使用基板貫孔使鐵電可變電容連接至矽基板背面的接地面。量測結果顯示，天線操作頻率固定於9.7 GHz，並無頻率可調的效果。我們發現，頻率不可調的原因為鈦酸鍶鋇薄膜退火溫度太低；而操作頻率偏移至低頻很多的原因為佈局瑕疵，造成電容負載中含有原先沒預期到且電容值頗大的氮化矽電容。在本論文中，我們成功地實現了以BCB為介電質並使用鐵電可變電容的頻率可調微帶貼片天線。另一方面，我們也成功使用矽基板貫孔技術製作出電容負載微帶貼片天線；雖然量測得的天線操作頻率有偏移且無法調整，但已知其原因，未來解決後應可達到預期性能。 ;The operating frequency of an antenna can be made reconfigurable by incorporating tuning elements. In this thesis, microstrip patch antennas are loaded with variable capacitors (varactors) to acquire frequency tunability. We design and fabricate two kinds of frequency-reconfigurable microstrip patch antennas, both of which use ferroelectric varactors with barium strontium titinate (BSTO) as the dielectric material for the capacitive loading. One of the microstrip patch antennas uses benzocyclobutene (BCB) as its dielectric whereas the other patch antenna uses high-resistivity silicon substrate. The operating frequency of the frequency-reconfigurable patch antenna with BCB as its dielectric is set at around 15 GHz. The ferroelectric capacitors and the patch are connected using the BCB stacked via process developed by our lab. Measurement results show that, when the bias voltage of the varactor is tuned from 0 V to 25 V, the operating frequency of the antenna varies from 13.8 GHz to 14.3 GHz, which translates into a 3.5% frequency tuning range (FTR). The operating frequency of the microstrip patch antenna with high-resistivity silicon as its dielectric is also designed to be around 15 GHz. The ferroelectric varactors are connected to the ground plane on the backside of the silicon substrate by through substrate vias (TSVs). Measurement results of this antenna show that the operating frequency is fixed at 9.7 GHz. No frequency tunability is observed. We find that the reason why the antenna is not tunable is because the annealing temperature for the BSTO thin film is too low for this sample. As for the large frequency shift, it is due to a mistake in layout. The layout mistake results in an unexpected silicon-nitride capacitor with a large capacitance, which becomes part of the capacitive loading. In this thesis, we successfully realize a frequency-reconfigurable microstrip patch antenna with BCB as its dielectric and with ferroelectric varactors as its capacitive loading. On the other hand, we successfully fabricate a capacitively loaded microstrip patch antenna using the TSV process we develop. Though the measured operating frequency has deviated from the designed value and cannot be tuned, we have discovered the reasons that result in these problems. We believe that the expected performance can be obtained after these issues are resolved.
Appears in Collections:	[Graduate Institute of Electrical Engineering] Electronic Thesis & Dissertation

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