The top copper cladding has a pattern as show in the figure below. The dimension
ID: 2083625 • Letter: T
Question
The top copper cladding has a pattern as show in the figure below. The dimensions are L_1 = 5.5 mm, L_2 = 4.3 mm, W_1 = 2.3 mm and W_2 = 1.6 mm. The bottom, infinite copper plane is separated from the top metal by 0.9 mm. Assume the relative dielectric constant of material between the top and bottom conductors is epsilon_r = 3. The right side of the circuit extends to z = infinity. The region that includes the two lengths L_1 and L_2 is called the "unit cell." Use the ABCD parameters where necessary. (a) Calculate the frequency of the propagating propagation wave such beta_1 L1 + beta_2 L_2 = pi, (b) Calculate the input impedance Z_in, (c) Calculate the minimum number of unit cells that are required to the make the reflection coefficient |r| > 2 at the point "a" on the transmission line.Explanation / Answer
There are four main techniques used today in the UK and mainland Europe for copper cladding a building:
When selecting size of a cladding element, take wind-loadings into account, and also consider the standard sizes available of the sheet (or coil) pre-material, to minimise material wastage through off-cuts. This helps to reduce costs.
The choice of which system to use depends on the aesthetic effect required, and building geometry can also have an influence on the choice.
Copper cladding is very durable, lightweight compared to other materials and techniques, and at the end of the building life is also 100% recyclable.
Depending on metal prices, copper may be a very cost-effective cladding and roofing material. With good building design, materials choice and craftsmanship, copper roofing or facade cladding may be cheaper than slates or concrete tiles, especially when one takes into account the lasting colour, durability, maintenance-free and lightweight nature of the cladding.
Because the UK code of practice for "hard metal" cladding (as opposed to lead cladding) is quite old - CP143: part 12 (1970) - the major manufacturers have to provide detailed technical advice and information for architects, designers and builders, and cultivate skilled installers with years of experience to draw on.
Typically, an installer of hard metal roofing and cladding must put in around 8–10 years on-the-job in order to achieve a respectable experience on a work site.
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