Development of Power Amplifier Modules with Embedded Passives for LMR (Land Mobile Radio) by Using LTCC-M Technology

摘要

LTCC-M (Low Temperature Cofired Ceramic on Metal) is one of MCM-C (Multichip module on cofired ceramic) technologies and has advantages in embedding passives owing to its dimensional stability after firing (zero shrinkage in x-, y-directions) with the general advantages of multichip modules and ceramic packaging. A power amplifier module (PAM) with embedded passives for LMR which operates at 440～470MHz was developed by using LTCC-M technology. Five resistors (three below 100Ω/sq. and two above 100Ω/sq.), three capacitors (330pF, 660pF and 1330pF) and three inductors (4.7nH, 12nH and 27nH) were embedded in the PAM, and all the embedded passives showed the tolerance of 10 to 20%. Metal core was used as an electrical ground plane and microstrip line was employed to match impedance between amplifying stages to achieve high efficiency. The three staged power amplifier modules showed 27.5 dB power gain and output power of 7 watts with the efficiency of 50%.