A compact DC-10 GHz SP7T RF MEMS switch

This paper presents a compact SP7T RF MEMS switch based on symmetrically designed radial series switches, in an area of 470 × 470 µm² (not including the CPW port transmission lines). The SP7T radial switch achieves a simulated contact and release force of 0.3 mN for an actuation voltage of 95 V. The switch achieves an isolation of 50-19 dB and an insertion loss of 0.3–1.2 dB at 0.1–10 GHz. The switching time is ∼10 µs. A cold-switched reliability larger than 10⁸ cycles with an RF power of 100 mW and 300 mW has been achieved, which is the required power for 3G and 4G systems. The application areas are in high performance compact switching networks for wireless systems. To our knowledge, this represents the most compact SP7T RF MEMS switch achieved to-date.

I. Introduction

Single-pole multiple-throw switches are broadly utilized in modern communication systems with several 2G/3G/4G standards such as cell phones and tablets. This area has been dominated by SOI and SOS switches due to their capability of providing high-port SPNT switches , and RF MEMS switches, with their inherent lower loss, higher isolation and linearity have not been able to compete in terms of port-count [1]–[2]. It is therefore important to develop an RF MEMS switch capable of switching 6–12 ports in a small chip area, since area is directly proportional to cost in large-volume manufacturing processes [3]–[6]. Also, SOI/SOS SP8T and SP12T switches, while having excellent performance up to 2.7 GHz, quickly fail in terms of insertion loss and isolation above 3 GHz due to their inherent large off-state capacitance and low-pass tuning networks. RF MEMS switches can be operated up to 10 GHz with a large number of ports, and are therefore useful for satellite switching network and other applications such as wideband (defense) radios [7].