本工作研究金屬高度對具有超穎材料之介電濕潤盒的電磁共振影響。在玻璃基板上製做出不同高度的光阻圖案，接著將銀薄膜沉積在光阻圖案上，用以製做出具有高深寬比的分裂共振環(high-aspect-ratio split ring resonators, HAR-SRRs)。另外，將具有圖案化的氧化銦錫(indium tin oxide, ITO)塑膠基板(PET)覆蓋上介電材料，用以製做電極板。將甘油油滴放入兩基板中央並封盒成介電濕潤(electrowetting-on-dielectric, EWOD)元件。利用介電濕潤驅動盒中液滴移動，改變HAR-SRRs之周圍介質，使得HAR-SRRs的共振頻率可被電壓調控。 在EWOD元件中，液滴在高深寬比結構的表面具有三種狀態。第一種狀態是液滴完全埋浸於高深寬比結構中(定義為K=1)，第二種狀態是液滴完全懸浮於高深寬比結構的表面上(定義為K=0)，第三種狀態是液滴介於第一種狀態與第二種狀態之間(0 < K < 1)。在電磁模擬中加入K值，可以推測甘油液滴在HAR-SRRs表面上的狀態。當甘油埋浸於結構中(K=1)，HAR-SRRs所感受的折射率差異達到最大；當甘油完全懸浮於結構上(K=0)，HAR-SRRs所感受的折射率差異達到最小。因此，甘油在HAR-SRRs表面上的狀態對共振頻率變化具有明顯的影響。 本研究開發共振頻率可調控的兆赫波濾波器，最大可調控的範圍為0.33 THz。這樣濾波器優於利用液晶所製做的兆赫波濾波器。因此，本研究所開發的兆赫波濾波器可以應用在兆赫波成像及兆赫波生物檢測上。 This work studies the effect of the height of metal films on the electromagnetic resonance of electrowetting-on-dielectric (EWOD) devices with metamaterials. Photoresist is patterned on a glass substrate, and then the patterned photoresist is deposited with a sliver film. The high-aspect-ratio split ring resonators (HAR-SRRs) are fabricated from the glass substrate with the patterned sliver film. An ITO-coated plastic substrate is patterned as an electrode plate. A patterned dielectric layer is deposited on the electrodes. A glycerin droplet is sandwiched between the glass substrate with the patterned sliver film and the plastic substrate with the patterned electrodes. The EWOD device is fabricated after polymer gel seals the glass and plastic substrates. Three states will exist as a droplet is placed on a HAR structure. The first case is the state in which the droplet is fully embedded into the HAR structure (defined as K = 1). The second case is the state in which the droplet is fully suspended on the HAR structure (defined as K = 0). The third state is between the two states (0 < K < 1). The K parameter is introduced into the electromagnetic simulation to inspect the state in which the droplet exists. As the glycerin droplet is fully embedded into (suspended on) the HAR structure [i.e. K = 1 (0)], the HAR-SRRSSs experience the maximum (minimum) change in the refractive index of the medium that surrounds the HAR-SRRs. Therefore, the state of glycerin droplet is the key parameter for the simulation in which the shift of the resonance frequencies of the HAR-SRRs is performed. This work fabricates a frequency tunable terahertz filter with the maximum frequency tuning range of 0.33 THz. Such a filter has a lager frequency tuning range than liquid-crystal-based terahertz filters. The frequency tunable terahertz filter can be used in terahertz imaging and terahertz biosensing.
