Duration: 2 hours 30 minutes
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Reply the controlthcoming questions on the Smith Chart and its applications.
(a) Starting from the limitation of Thought Coefficient, illustrate the reading of the Smith Chart. It is NOT expedient to follow the equations control the true impedance and true reactance dispersions. [8 marks] It is a polar frame of the many-sided thought coefficient. It is also disclosed as the 1-port scattering parameter s or s11, control thoughts from a normalized many-sided carry impedance z = r + dx; [4 marks] [2marks] [2marks].
(b) Consider the transmission method tour under (Image 1). Use the Smith Chart to experience SWR on the method, the restore missing, the thought coefficient at the carry, the carry extinguished voting, the input impedance to the method, the removal to the primeval voltage narrowness, the removal from the carry to the primeval voltage zenith. [9 marks] 0. 8 Wavelength Z0 =50 ? ZL =70+j40 ? Zin Image 1 1mark control each reply ate control the ultimate couple (2 marks) (c)A carry impedance of ZL = 100-j150 ? is to be tallyed to a 50? method using a uncombined shunt-stub tuner. Experience couple solutions using short-circuited stubs. [8 marks] 2 marks each control the controlthcoming disgusting replys [pic]
(a) Consider an imperious microwave transistor with scattering matrix [S], conjoined to fountain and carry impedances as shown in Image 2. Follow the controlthcoming equations abextinguished (in and (out. [7 Marks] with regard to image 1, the thought coefficient is seen looking controlward the carry is timeliness the thought coefficient seen looking inland the fountain is [1 Marks] in unconcealed, the input impedance of the terminated couple-port netlabor gain be mismatched with a thought coefficient fond by (in, which can be defined by the controlthcoming separation. From S parameters limitation, Eliminating V2-, and solving control [4 Marks] Similarly, (extinguished can be obtained. [2 Marks]
(b) In a transistor oscillator, a one-port negative-resistance is effectively created by terminating a theoretically transient transistor with an impedance fitted to animate the design in an transient district as shown in Image 2. [pic] Image 2 Assuming that S parameters of the transistor in a sordid-portico delineation are S11=(2. 18, -35(), S12=(2. 75, 96(), S21=(1. 26, 18(), S22=(0. 52, 155(). Design carry and terminating networks using a coalition of one-eighth and a pity wavelength impedance transformers control a microwave oscillator. Content not attributable attributablee that the uprightness dispersion can be fitted using the controlthcoming equations [18 Marks].
S11 is totally vast, which resources that the sordid portico transistor delineation is transient
The nucleus and radius of the extinguishedput uprightness dispersion in the (T flatten are CT=(1. 08, 33(), RT=0. 665 [4 Marks]
Since |S11|=2. 18>1, then the firm district is internally the uprightness dispersion, this gives a vast totality of insubservience to appropriate (T flatten.
T is separated as (0. 59, -104). Then an impedance tallying netlabor is used to turn ZT into 50Ohm tally carry
From (T, (in=(3. 96, -2. 4(). It is obtained from [pic] • Zin can be set-up to be (-84-j1. 9)Ohm, and then ZL(()= -Rin(()-jXin(() • A tallying netlabor is clarified to tally ZL with 50Ohm carry [10 Marks] Based on the controlthcoming equations, an impedance tallying netlabor can be fitted (T is separated as (0. 59, -104(), ? T can be set-up as • Zin can be set-up to be (-84-j1. 9)Ohm, and then ZL(()= -Rin(()-jXin(()=84+j1. 9
Question 3 Reply the controlthcoming questions abextinguished microwave amplifiers:
a)Show that control a unilateral design, where S12=0, the ( -parameter proof implies that | S11 | < 1 and |S22 | < 1 control perpetual uprightness. Where the ( -parameter proof is controlmulated as [8 marks].
b) Use the ( -parameter proof to state which of the controlthcoming designs are perpetually firm, and of those, which has the greaproof uprightness. [6 Marks].