Answers to LCP for Microwave Packages and Modules
Answers to RF Cafe Quiz #47

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LCP for Microwave Packages and Modules - RF Cafe Featured BookThis quiz is based on the information presented in LCP for Microwave Packages and Modules, by Anh-Vu H. Pham, Morgan J. Chen, and Kunia Aihara.

1.  What does LCP stand for?

d)  Liquid Crystal Polymer
Liquid crystal polymer (LCP) is a plastic material with barrier properties similar to ceramic crystal.
(see page 1)

2.  What does "liquid crystal" mean?

a)  A phase of matter that has partly solid and partly liquid properties
(see page 17)

3.  What are the advantageous electrical properties of LCP material?

a)  Low dielectric constant and loss tangent
(see page 20)

4.  How is LCP used in microwave and mm-wave circuits?

c)  As a substrate for printed circuits
(see the entire book)

5.  What is the maximum ratio of die size to package size for a chip-scale package (CSP)?

b)  1.2
As defined in IPC/JEDEC J-STD-012, chip-scale packaging (CSP) refers to a packaging method where the final package area dimensions are no larger than 1.2 times the die.
(see page 72)

6.  What is an advantage of using lumped element embedded capacitive coupling on an LCP substrate?

c)  It eliminates the need for a feedthrough via
The lumped element capacitor inherently blocks DC and eliminates the need for a via. A disadvantage is that lumped element printed capacitors are physically large.
(see page 132)

7.  What happens to common-mode signals at the single-ended output port of an ideal balun?

d)  They are completely reflected back away from the port
Common-mode signals are completely rejected and reflected back from a lossless balun since only differential signals are converted to single-ended signals and allowed transmission.
(see page 166)

8.  What is a primary advantage of a long time delay (LTD) line over a phase shifter when used in pulsed power applications?

a)  LTD line is inherently wideband
Unlike a phase shifter, LTDs are inherently wideband and thus are ideal for pulse transmissions on phased array antenna systems.
(see page 193)

9.  What property of LCP material make it good for hermetic packaging?

b)  Ultra-low moisture absorption
LCP material has ultra-low moisture absorption and permeation close to that of glass.
(see page 226)

Posted  10/18/2012