An integrated passive device (IPD) technology has been developed in order to achieve lower cost, further miniaturization, and higher performance in microwave devices applied to the front‐end modules of wireless communication system.This article describes a compact wireless local area network (WLAN) balun suitable for wireless system application using IPD technology based on an SI‐GaAs substrate. It shows very good RF performances in spite of its small chip size and low cost, compared to those found in recent literature. A small outline transistor packaging technology with a three‐dimensional electromagnetic simulation is reported. The fabricated WLAN balun has an insertion loss of < −0.25 dB and a return loss of > −25 dB. The phase imbalance was measured to be less than 3° and the amplitude imbalance is less than 0.5 dB; its dimensions are 800 μm × 700 μm × 200 μm. This compact WLAN balun can be used for a variety of applications in the microwave field. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1301–1305, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26801