RF and Microwave Engineering

End of Class

2009-09-23T07:04:00.003+08:00

Important Announcement

2009-09-15T22:05:00.002+08:00

For the mid-term test on thursday, you can bring in a piece of "cheat sheet" size A4. You can only write on one side of the sheet. Write your name and matriculation number on the sheet. This sheet must be submitted along with your answer scripts. Notes and books are not allowed.

Bring along your own protractor, drawing tools, etc. No sharing is allowed.

Good luck.

Reflection coefficient of a terminated network

2009-09-06T22:25:00.002+08:00

If the reflection coefficient of a network terminated with a matched load is S11, what would the reflection coefficient be when the load is generally ZL?

Maximum power transfer

2009-09-06T22:19:00.001+08:00

For a network with a scattering parameter S11, what would be the condition for maximum power transfer from a source? Satisfy yourself that the condition is true.

Reference text

2009-09-03T16:50:00.001+08:00

follow my twit for the name of the author who i referred to in class today

Review of microwave propagation and scattering parameters

2009-08-31T23:03:00.000+08:00

I hope the quiz last week tested briefly your understanding of radio wave propagation. Microwave propagation is interesting because of the many ways the waves interact with objects and media along the path.

You should by now appreciate the mechanisms of microwave propagation. Lest one forgets, we are talking of not only terrestrial but also space communications using microwaves.

The next topic to be discussed would be microwave networks. Here, a network is meant to be a device (active or passive) that accepts signals at microwave frequencies. We would see that low frequency network representation fails at microwave frequencies. We need to introduce a new set of parameters to describe the networks.

At microwave frequencies, we do not use open-circuit and short-circuit tests as these would introduce oscillations and irradiations. To ensure the system is stable, we use matched load tests. The result would be the scattering parameters.

see you in class.

Quiz #1

2009-08-19T10:32:00.003+08:00

There will be a quiz on Tuesday, 25 August. The topic will be on propagation covering:

1. Line-of-sight range and antenna heights,
2. Free space loss calculation
3. Fresnel zone clearance
4. Diffraction and shadow zone
5. Ducting, sub- and super-refraction propagation

Be Prepared

Follow me on Twitter

2009-08-19T08:16:00.000+08:00

i'm on Twitter. look for radioscientist@twitter

Class on Tuesday 25 August

2009-08-19T07:57:00.002+08:00

There will be a class on Tuesday, 25 August. Time as usual at 11:00am

We will continue our discussions on propagation of radiowaves with emphasis on microwaves.

Recitals for the class have been given in previous posts.

Microwave article and reference text

2009-07-30T16:45:00.004+08:00

1. Primer on propagation

Books:

1. Radio Engineering by G. K. Mithal, Khanna Publishers.

2. Radio WAve Propagation and Antennas by John Griffith, Prentice Hall.

Class Schedule

2009-07-30T12:39:00.003+08:00

July:
30: Class #1

August:
27: Class #2

September:
1: Class #3
3: Class #4
8: Class #5
10: Class #6
15: Class #7 - Last Class

Welcome to Semester I of Session 2009/2010

2009-07-30T08:58:00.000+08:00

There will be a class on Thursday 30 July, 2009 at MRL.

The topic covered will be on microwave and tropospheric propagation. Read up on on this topic before class.

Assignments S-parameters

2009-03-10T14:40:00.004+08:00

In preparation for the tests, do these problems.

Pg. 245 of Pozar's 2nd Edition or Pg. 217 of 3rd Edition: # 4.5, 4.6, 4.8, 4.9, 4.16. Submit only 4.9 and 4.16, by 23 March to WARAS.

Class on 13/01/09

2009-01-11T01:10:00.002+08:00

The class on 13/01 will be conducted by Dr. Yusof. He will touch on microstrips.

Our propagation class will continue 27/01 which falls on CNY holiday. The replacement class will be decided soon.

Direct and reflected wave propagation

2009-01-05T22:45:00.003+08:00

Electromagnetic energy at microwave frequencies generally propagate in a straight line. It direction changes when it traverses a medium of a different refractive index than the one it is in. Another factor that can divert its direction is when it is reflected or scattered when it impinges on an electrically smooth or rough surface.

When the transmitter and receiver antennas are at heights Ht and Hr above ground and separated by distance D, the signal received would be a resultant of the direct wave and reflected wave. Show and convince yourself that the differential distance between the reflected and direct wave is dependent on the heights of the antennas and the distance. Derive the relationship.

From the result, what would be the phase of the resultant electric field. Explain why the result is as such.

Welcome to Semester II of the 2008/09 Session

2008-12-31T22:41:00.005+08:00

As most of you are aware, class started yesterday, 30 December, 2008. For those of you who did not make it, please consult your classmates.

As agreed, class will meet every Tuesdays, from 11:15 to 14:00. The meeting place would be the MRL room at the FKEE complex.

The course content will be distributed at the next class.

For the first class reading assignment, visit this site for a good discussion on VHF/UHF/microwave propagation. This article is just a primer and you are expected to read the reference text as discussed in class.

BTW, as this is posted on the last day of the solar year, I wish everyone a happy new year.

Network Analyser Demo at WARAS

2008-10-19T18:43:00.006+08:00

I hope everyone had a good time during the demo. You may need to use the equipment more to fully appreciate its usefulness.

You can visit here to download the photos.

Good luck in the forthcoming finals.

FIELD EFFECT TRANSISTOR AMPLIFIER DESIGN

2008-09-17T07:33:00.007+08:00

You can download an application note of the Motorola AN423 RF FET amplifier design technique.

One site where you can test your answers to problems on RF amplifier designs can be found here.

www.microwaves101.com

2008-09-16T10:41:00.002+08:00

Check out this website. It has lots of interesting articles on rf and microwaves.

Assignment

2008-09-11T08:23:00.002+08:00

Read Chapter 4 of Pozar's book (3rd Ed) and do the following:-

Qns. 4.1, 4.2, 4.3, 4.4, 4.6, 4.7, 4.8, 4.9, 4.10.

Submit by Monday Evening 5.00pm

GL

Deterministic approach to designing conditonally stable amplifiers

2008-09-09T11:45:00.000+08:00

http://www.mediafire.com/?j1nyqotzqzm

Different kind of load on a transmission line

2008-08-15T17:55:00.000+08:00

See if you can work out the SWR with these two moving loads!

Time is up

2008-07-31T17:00:00.000+08:00

By the time you read this, the deadline for submission of the first assignment is over.

Eventhough you are late, you still have to submit and i will deduct 50% from your grade. Good luck

Reminder resubmission

2008-07-28T17:00:00.001+08:00

Just to remind you that you need to send in both the hardcopy and softcopy of your assignment. The softcopy can be emailed to azlin at uthm dot edu dot my.

Name your file like so: 20080731 "your student number".doc

If your student number is BT12345, then your file name should be: 20080731 BT12345.doc

Failure to comply will be disastrous.

Poll

2008-07-28T08:28:00.001+08:00

I have posted a poll but only one person has responded. There are more than 20 students enrolled in the class. Where are you?

Like i said in the first class, take this website seriously. i would like to know what students think of the profession.

If you have not voted, then do so before the deadline.