- Buyers Guide
Military Microwaves Supplement
Published February 13, 2006
From: Adeline Rebeiro, Twin Antennas
Could you provide details of the various divider networks used in microstrip patch antennas? I am trying to design a microstrip patch array for 2.4 GHz and 19 dBi gain. From a single patch, I get a gain of around 9 dBi. Do I need to go to an array configuration? What method do you suggest should be used to combine the patch elements?
From: Tapas Bhuiya, SAMEER
How is insertion loss related to the return loss of a filter? Is it true that good return loss of an antenna is always efficient (efficiency is more, for example)?
From: Subhash Janakiraman, Icon Systems
I have a question on a RF board. The system works at 902-928 MHz ISM band. I am connecting two boards using a header. The PCB dielectric material is FR4 and they are six-layer boards. The distance between the two boards is 0.5 inches. I am concerned about the antenna traces getting connected through this header. Is this arrangement fine or am I supposed to have some effects due to the connector metal acting as a radiating source? Please explain.
From: Syed Shafqat Hussain, University of Leeds
I am a novice trying to research loss compensation in microwave filters, but could not find any relevant material on the Internet or in books. Could you please help me understand this topic and also guide me to where can I find reading material relevant to the topic?
From: Murali Ellanti, LNT Electronics
What are the CW and pulse power handling capabilities of improved SMA connectors at 18 GHz? I want to handle 100 W CW and 3 kW pulse. Can I use SMA connectors?
From: Ashim Jolly
Could you let me know where I can acquire the circuits for mobile phones that I can develop in my lab? I am an engineering student and require some designs that I can simulate in software like PSPice, etc. Could you also recommend some other ways of learning how to build your own mobile phone?
From: Moazzam Loynmoon, SIGNET
In a loop antenna a 1 Amp/Volt current transformer is required to terminate both ends of the loop. Output is single-ended. Frequency required is 19 kHz to 30 MHz minimum. Could you tell me how to fabricate it? I know that a toroid is required for the same.
Our customer would like to establish, on turn-key basis, a general-purpose RF/microwave workshop/lab to test/repair their radar assemblies.
From: John Bradin, Assa Abloy ITG
I am researching compact antennas for a 2.45 GHz WPAN. The radiation efficiency is (radiation resistance)/(radiation resistance + loss resistance). I believe that the correct calculation of the loss resistance for the case where the conductor thickness is > 5X (skin depth) is given by (loss resistance) = (conductivity/(skin depth))*(# of squares in the antenna conductor). There are other equivalent expressions that reduce to this. Is this correct? Given the amount of work in very small 2.45 GHz wireless devices, I am surprised not to see this concisely discussed. I have found a few cases where the skin depth issue is ignored. What am I missing?
Harlan Howe, Jr. received his BS degree in optics from the University of Rochester in 1957. He has been actively engaged in the microwave industry for 48 years, first as a design engineer and then as an engineering manager. In 1990 he became the publisher/editor of Microwave Journal. He retired as publisher in 2001, but remains the editor. He is a Life Fellow of IEEE, past president of MTT-S and the recipient of an IEEE Third Millennium Medal in 2000 and the MTT-S Distinguished Service Award in 2005.
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