3- Below are stability circles for a certain transistor. S11 < 1 and S22 > 1. Circle the correct answer.

Transkript

1 1- A transistor has 11 > 1 and 11 < 1. Above, -l is the source stability circle and - is the load stability circle. Mark the stable and potentially unstable regions of each mith chart. 3- Below are stability circles for a certain transistor. 11 < 1 and > 1. Circle the correct answer.

2 5- Given 11 = , 1 =.1 96, 1 = 0, = a) What is the maximum power gain that can be realized with this transistor? b) What impedances should the matching circuits present to the transistor I/O for max gain? c) What is the max power gain that can be realized with this transistor when 1 = ? d) What impedances should the matching circuits present to the transistor I/O for maximum gain when 1 = ? a) G = =.1 = 18.9 = 1.6 db TU max Γ b) Γ = 11 = Z = = j48.4 Ω 1 Γ 1+ Γ Γ = = Z = = j53.7 Ω 1 Γ Z = j00 Ω, Z = 80 + j380 Ω in c) Max gain 1.11 db d) Input impedance = j150, Output impedance = j30

3 4- -parametreleri (50 ohm) aşağıda verilen transisitor ile 1 GHz'te bir kuvvetlendirici tasarlanacaktır. a) Bu transistorun kararlı olup olmadığını belirtin. b) Maximum kazancı ve buna karşılık gelen Γ, and Γ değerlerini bulun. c) mith Chart kullanarak -devresi ile sadece giriş devresini tasarlayın. 11= , 1= 6 180, 1= 0, = An amplifier is to be designed for max gain using a BJT with s-parameters at 1 GHz in a 50 ohm system as 11= , 1= 6 180, 1= 0, = a) Determine whether this BJT is unconditionally stable. b) Calculate the the maximum transducer gain and the corresponding Γ, and Γ values. c) Design -section matching network using lumped elements. Your amplifier must look like below. Design only the input. Attach your mith Chart. Unconditionally stable, G = 73.9= db 1+Γ in Zin= Z0 = Z0 = 50( Ω j.08086) = 1.67 j Γin 1 11 = 5.19 nh, C = pf 1 C = pf, = nH 1 T

4 4- A transistor requires a source and load reflection coefficients as Γ = and Γ = for a desired regime of amplifier operation. Design a single shunt stub open circuit tuner input and put matching networks as below. Attach your mith Chart. 4- Aşağıdaki kuvvetlendirici için yansıma katsayıları Γ = ve Γ = ise şekildeki uyumlandırma devrelerini tasarlayın. mith Chart i kağıdınıza ekleyin. 1+Γ Zin= Z0 = j.5403ω d1= 0.11, λ l1= 0.067λ ord1= λ, l1= 0.434λ 1 Γ 1+Γ Z= Z0 = j ω d= λ, l= 0.067λ ord= 0.30 λ, l= 0.105λ 1 Γ

5 1- Asağıda 6.0 GHz te 50 ohm sistemınde s-parametreleri verilen bir FET ile kuvvetlendirici tasarlanacaktir. 11= , 1=.4 3, 1= 0, = a) FET in şartlı veya şartsız kararlı olup olmadığını bulun. b) Maksimum unilateral tranducer kazancını ve buna göre Γ, ve Γ değerlerini hesaplayın. c) Giriş/Çıkış devresi için toplu elemanlarla aşağıdaki şekildeki gibi uyum devresi tasarlayın ve mith i kağıdınıza ekleyin. Isteyen giris isteyen cikis devresini tasarlayabilir fakat devre elemanlari asagidaki gibi olmalidir An amplifier is to be designed for max gain using a FET with s-parameters at 6.0 GHz in a 50 ohm system as 11= , 1=.4 3, 1= 0, = a) Determine whether this FET is unconditionally stable. b) Calculate the the maximum transducer gain and the corresponding Γ, and Γ values. c) Design -section matching netwok using lumped elements.. Your amplifier must look like below. Design only the input or put. The coice is yours. k= > 1, = 0.45< 1 unconditionally stable G 1 1 = = = db 1 1 TUmax Γ = 11= Zin= Z0 = 1. j4.1ω 1= nh, C1= pf Γ = = Z= Z0 = j53.ω C= pf, C3= 0.71pF 1

6 1- Asağıda 6.0 GHz te 50 ohm sistemınde s-parametreleri verilen bir FET ile kuvvetlendirici tasarlanacaktir. 11= , 1=.4 3, 1= 0, = a) FET in şartlı veya şartsız kararlı olup olmadığını bulun. b) Maksimum unilateral tranducer kazancını ve buna göre Γ, ve Γ değerlerini hesaplayın. c) Giriş/Çıkış devresi için toplu elemanlarla aşağıdaki şekildeki gibi uyum devresi tasarlayın ve mith i kağıdınıza ekleyin. iz sadece girişteki devre elemanlarını bulun. 4- An amplifier is to be designed for max gain using a FET with s-parameters at 6.0 GHz in a 50 ohm system as : 11= , 1=.4 3, 1= 0, = a) Determine whether this FET is unconditionally stable. < 1, < 1, < 1, k > 1 FET is unconditionally stable 11 b) Calculate the the maximum transducer gain and the corresponding Γ, and Γ = = , Γ = = G ,, = = 16.6= 1.dB TUmax Γ values. c) Design the input/put matching circuit using -section matching sections using lumped elements as seen in the figure. Attach your mith Chart! input put 1 Zx 0 C= = 1.53 pf = = 0.78 nh ωzx 0 c ω Z0 Z0 = = nh = = 0.98 nh ωb ωb

7 4-10 GHz te s-parametreleri 11= , 1= 0, 1= 1.7 5, = verilen bir FET kullanılarak kuvvetlendirici tasarlanacaktir. a) FET in kararlı olup olmadığını bulun. b) Maksimum kazanç için Γ, ve Γ değerlerini hesaplayın. c) Maksimum tranducer kazancını hesaplayın. d) Çıkış devresi için single shunt stub open circuit tuner uyum devresi tasarlayın. Devreyi cizin ve mith i kağıdınıza ekleyin. 4- An 10 GHz amplifier is designed using a FET with s-parameters: 11= , 1= 0, 1= 1.7 5, = a) Determine whether this FET is unconditionally stable. b) Find source and load reflection coefficient for maximum transducer gain design. c) Calculate the value of the maximum transducer gain. d) Design the put matching circuit using single shunt stub open circuit tuner. Assume the load impedance is 50 ohm. Draw the circuit and attach your mith Chart! a) < 1, < 1, < 1, k> 1 FET is unconditionally stable b) Γ =Γ = = , Γ =Γ = = c) G d) 11 in = = 14.07= db TUmax input: point Γ = on C. convert it admittance by Γ = intersect 1+ jb circle by moving from 0.6λ 0.38λ so d1= 0.066, λ l1= 0.147λ put: point Γ = on C. convert it admittance by Γ = intersect 1+ jb circle by moving from 0.093λ 0.05λ so d= 0.11, λ l= 0.98λ

8 4- A transistor requires a source reflection coefficient Γ = for a desired regime of amplifier operation. Design a single shunt stub input matching network to transform 50 ohm source impedance to the desired source reflection coefficient. 1) plot Γ = zs = j0.31 and transform to admittance ys= 1.6 j1.58 ) Plot constant VWR circle and intersect 1+jb circle at y= 1± j1.3 solution 1: + j1.3 o.c. stub gives shortest l 1 = 0.146λ g solution : j1.3 s.c. stub gives shortest l = = 0.104λ g 3) Now move from 1± j1.3 to ys along constant VWR circle (WTG) solution 1: d1= = 0.131λ g solution : d = ( ) = 0.474λ g d is much grater than d1 hence solution 1 appears to be the better choice (could improve further with balanced o.c stubs)

9 1- The put of a transistor with s-parameters at 10 GHz given below in a 50 Ω system is terminated in a 50 Ω load as seen in the figure below. Design a single stub series tuner that matches the input of the transistor to a 50 Ω transmission line. Attach your mith Chart. V G 50 Ω Input Matching Network [ ] 50 Ω j145 j e 0.0e [ ] = j65 j35.55e 0.35e Γ =, Z = 50(1 + )(1 ) = 50(0.3+ j0.3) Ω in 11 in i) The shortest line section is the one that transforms Zin into an impedance with a real part of unity when rotating towards the generator (see mith Chart). We get l/λ = = Hence: l b = x 30 mm = 4 mm ii) To match the transformed input impedance to 50 Ω we add a negative reactance of j1.7 in series. The shortest stub having this input reactance is an open-circuited stub of length l/λ = = Hence: l c = x 30 mm =.55 mm. A short-circuited stub would be λ/4 or 7.5 mm longer.

10 3- The s-parameters of a transistor at 10 GHz in a 50 Ω system are given below. Design a lumped element input matching network that matches the input of the transistor to a 50 ohm generator when the put of the transistor is terminated in a 50 Ω load as shown in the figure below. The first element of the matching circuit next to the transistor must be an inductor. Attach your mith Chart GHz te 50 ohm sisteminde bir transistorun s-parametreleri aşağıda verilmiştir. Bu transistorun girişini generatore uyumlandırmak için gereken toplu eleman uyumlandırma devresini tasarlayın. Uyumlandırma devresinin transistor tarafındaki eleman bobin olmalı. mith i kağıdınıza ekleyin. V G 50 Ω Input Matching Network [ ] 50 Ω Γ in = 11. Zin= 50(1 + 11)(1 11) = 50(0.3+ j0.3) Ω j145 j e 0.0e [ ] = j65 j35.55e 0.35e jx j xz ω 0 1 = 0.1 = = H, BY jb= j = = ω C F

11 - 50 sisteminde s-parametreleri 11= , 1= 0, 1= , = olarak verilen transistor ile G TU,max için kuvvetlendirici tasarlanacaktır. a) G TU,max değerini hesaplayın. b) Giris devresi için single shunt stub open circuit tuner uyum devresi tasarlayın. c) Cikis devresi için single shunt stub open circuit tuner uyum devresi tasarlayın. - A microwave transistor amplifier is to be designed for G TU,max using a transistor whose s- parameters in a 50 ohm system are given by 11= , 1= 0, 1= , = a) Find G TU,max. Γ = = Γ = = G = = = , , dB 1 1 G = = 1.99= 3dB, G = = 1.35= 1.3dB, G = 18.3dB max max TU,max b) Design the input matching network single shunt stub open circuit tuner. c) Design the put matching network using single shunt stub open circuit tuner.

12 1-A transistor has the following scattering parameters for a 50 ohm characteristic impedance at 1 GHz: 11 = , 1 = , 1 = 0, = Match the put of this transistor to a load impedance of 4 + j 35 ohm using two reactive lumped elements at 1 GHz. Make sure that your design allows placement of the load on the transistor with influencing the transistor bias. A smith chart is attached for your use.

13 4- A particular transistor requires a source reflection coefficient Γ s = for a desired regime of amplifier operation. An alternative design uses λ g /4 transmission line section immediately after the 50 ohm source impedance followed by a shunt stub of length 3λ g /8 (as shown below) to match to the desired Gs. Determine the required characteristic impedance (Z 01 and Z 0 ) of the λ g /4 through line and the shunt stub, and your choice for the stub type (oc oc) and length, to accomplish the match with due consideration of BW. Include a sketch of a microstrip implementation of your design (you do not need to calculate the specific microstrip dimensions.) (1) plot Γ = zs= 0.3+ j0.31 () transform to admittance zs= 1.6 j1.58. Ys lies on constant g circle g=1.6. (3) Draw constant VWR circle through g=1.6 (g=1.6 corresponds to r=0.65) (4) R=r50=31.5 ohm. Use quarterwave transformer to get to this impedance value Z =50 ohm, Z s =31.5 ohm. Z 01= = 39.5Ω. (5) transform to admittance g=1.6 Now just add a susceptance jb=-j1.58 to get to the desired ys. However we are constrained to use a λ g /8 or 3λ g /8 stub of impedance Z 0. jb=jby 0 = -j recall a λ g /8 or 3λ g /8 stub can give jb = ± j1 choose normalized impedance Z 0 to convert jb to desired jb. ince we need a negative susceptance, choose a λ g /8 sc stub for better BW

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15 1- In each of the stability circle drawings shown below, indicate clearly the possible locations for a stable source reflection coefficient. 1- Aşağıdaki mith Chart larda kararlılık daireleri çizilen transistorler için, giriş (kaynak) yansıma katsayısının ( Γ ) kararlı olacağı bölgeleri tarayınız. s C s C s K < 1, > 1, < 1 11 K < 1, > 1, < 1 11 C s K > 1, > 1, 11 < 1, > 1 K 11 > 1, > 1, > 1, > 1 C s C s K > 1, < 1, 11 < 1, > 1 K 11 > 1, < 1, < 1, < 1 C s C s K < 1, > 1, < 1 11 K < 1, > 1, < 1 11 C s K > 1, > 1, 11 < 1, > 1 K 11 > 1, > 1, > 1, > 1 C s C s K > 1, < 1, 11 < 1, > 1 K 11 > 1, < 1, < 1, < 1

16 1- What is the purpose of a matching circuit on the input or put of a transistor circuit? To maximize power transfer. To reach a desired gain that is lower than the maximum gain. To change the impedance of the load oource. - Is this true or false? High frequency amplifiers have a high input impedance and a high put impedance. True 3- What are the effects of the mismatched impedances? ome of the voltage will be reflected. ome of the current will be reflected. Cancellation of voltages. 5- What is the difference between high frequency and low frequency amplifier design? The high frequency transistor has low gain. Feedback is large enough to cause stability problems. The operational frequencies.

17 7- You are asked to design a NA at 950 MHz. The parameters is shown below. 11 = , = , 1 = , 1 = 0.0. Also, it is found that the noise characteristics are described by F min = db, Γ opt = and R n = 0 ohms. a) What is the greatest gain that can be gotten from the device by proper matching of the input and the put? GT 1 1 = = 3.44 = 13.7 db max b) What is the noise figure under this matching condition? Γ s = 11 = , Γ opt = , R = 0 Ω, Z 0 = 50 Ω, F min = db 4R Γ Γ F = F + = 1.64 =.15 db n s opt min Z0 1+ Γopt 1 Γ ( s ) c) If the transistor is matched for minimum noise, what is the noise figure? To get minimum NF, Γ s = Γopt F = Fmin = db n d) What is the gain for the matching condition for minimum noise? What is the input VWR? Γ = Γ = , G s opt T s 1 s11 1 Γ 1 = =.15 = db 1 Γ 1 Γin Γs Γ in = 11 Γ a = = 0.353, VWR 1 Γ Γ in s in 1+ Γa = = Γ e) With an input match to minimize noise, how much noise power is contained in the put, in a frequency band 30 khz wide centered at 950MHz? N o = F(dB) + 10log[kTG T B] G T =.15, F = db, B = 30 khz, T = 90K (room temp) N o = -114 dbm a

18 4- A fully matched RF amplifier has the following parameters. 11 = , 1 = , 1 = , = a) Determine the stability factor , 1.08 = = k = = b) Determine the error assuming the unilateral case U = = 0.061, = 0.89, = 1.13 (1 )(1 ) (1 + U ) (1 U ) 11 Gt 0.51 db < < 0.55 db G tu c) Determine the source side reflection coefficient for a conjugate match. d) Determine the maximum transducer gain.

19 6- A low noise transistor has the following parameters: F min =.1 db, Γ opt = , R n = 3 Ω and B = 3 KHz. [ ] = a) If the transistor is terminated with Γ 1 = , and the source temperature is T = 10 K, find the internal noise of the transistor referred to its input. s b) Assuming the same termination, 1 Γ at the input, find the put termination, Z, that maximizes the gain.