Miniaturized rf transformer-based baluns for 802.11a/b/g WLAN modules embedded in organic package substrate

Two lumped-element baluns that utilize package-embedded symmetric differential inductors and embedded capacitors have been designed for WiFi and mobile WiMax applications. These baluns have very small form factor with an area of ≪ 3mm² making them ideal candidates for portable wireless communication devices such as ultra mobile personal computers. The fabricated baluns exhibit excellent electrical performance with measured phase and amplitude imbalances as low as 2 degrees and 0.15 dB, respectively in the frequency bands of interest. Insertion loss values as low as −1.5 dB was also observed.