scholarly journals Theoretical analysis of the characteristic impedance in metal–insulator–metal plasmonic transmission lines

2012 ◽  
Vol 37 (6) ◽  
pp. 1050 ◽  
Author(s):  
Hamid Nejati ◽  
Ahmad Beirami
2014 ◽  
Vol 2014 (1) ◽  
pp. 000838-000843
Author(s):  
Cenk ATALAN ◽  
Eyup TONGEL

Coupling capacitors or DC blocks are essential tuning elements in RF/microwave applications. Their role becomes imperative in cascade amplifiers to isolate drain voltages of preceding MMIC from the gate voltage of the following chip where both RF and DC signals are carried through the same line. The purpose of this study is to explain the benefits of a newly designed thin film coupling capacitor called as transmission line metal-insulator-metal capacitor (TL MIM Cap), which serves as a DC block capacitor in microwave circuits. This novel structure provides a unique solution, which cannot be achieved with traditional single layer ceramic capacitor (SLC) structure. It combines two discrete circuit elements into one: “Microstrip transmission line of required length and width” with a “serially attached coupling capacitor”. Thin film capacitive layers ranged from 0.5pF to 50pF, which are typically needed for microwave frequencies within 1–40 GHz, constructed and embedded into 50 Ohm impedance transmission lines in series. Substrates like quartz, glass, or alumina can be used to minimize losses and to achieve higher RF/microwave performance. We used copper traces as conductive layers for optimal conductivity. After manufacturing TL MIM Caps, we tested several capacitance values for 1pF, 5pF, 15pF and 30pF corresponding to a wide frequency range. The RF tests we performed showed that TL MIM Caps exhibited a minimum of 20dB return loss and a maximum of 0.3 dB insertion loss at 1–40GHz range. We also found our technique comes with some workmanship advantages in high frequency circuit assembly as follows: Traditional coupling capacitor attachment with silver epoxy on top of a microstrip transmission line is a manual operation, which requires well trained and experienced technicians. In contrast, using the TL MIM Caps in our high frequency hybrid modules, we found that the process caused errors were eliminated such as the micro short circuit effect caused by conductive epoxy. Therefore we improved yield in assembly stage of the circuits. In addition, improvements are observed in production processes such as less consumption of adhesives (epoxy), no technician failure caused wastes, elimination of extra curing process to attach capacitors, no short circuit inspection, rework, or re-cure operations to fix assembly errors. Last but not least, blocking capacitors are embedded into the microstrip transmission lines in TL MIM Caps. This ensures that having the lowest possible impedance since very short wire bond exists from the bond pad of the TL MIM Cap to the adjacent circuit element.


2011 ◽  
Author(s):  
Terrance O'Regan ◽  
Matthew Chin ◽  
Cheng Tan ◽  
Anthony Birdwell

2021 ◽  
Vol 11 (4) ◽  
pp. 1544
Author(s):  
Meguya Ryu ◽  
Yoshiaki Nishijima ◽  
Shinya Morimoto ◽  
Naoki To ◽  
Tomoki Hashizume ◽  
...  

The four polarisation method is adopted for measurement of molecular orientation in dielectric nanolayers of metal-insulator-metal (MIM) metamaterials composed of gold nanodisks on polyimide and gold films. Hyperspectral mapping at the chemical finger printing spectral range of 4–20 μμm was carried out for MIM patterns of 1–2.5 μμm period (sub-wavelength). Overlay images taken at 0,π4,π2,3π4 orientation angles and subsequent baseline compensation are shown to be critically important for the interpretation of chemical mapping results and reduction of spurious artefacts. Light field enhancement in the 60-nm-thick polyimide (I in MIM) was responsible for strong absorption at the characteristic polyimide bands. Strong absorbance A at narrow IR bands can be used as a thermal emitter (emittance E=1−R), where R is the reflectance and A=1−R−T, where for optically thick samples the transmittance is T=0.


2021 ◽  
Vol 4 (3) ◽  
pp. 2470-2475 ◽  
Author(s):  
Ayendra Weerakkody ◽  
Amina Belkadi ◽  
Garret Moddel

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