Robert Lempkowski

A MEMS-based tunable coplanar patch antenna fabricated using PCB processing techniques

In this paper, a tunable coplanar rectangular patch antenna (CPA) designed using a MEMS varactor is reported. The MEMS varactor is monolithically integrated with the antenna on Duroid substrate using printed circuit processing techniques. Specifically, the MEMS varactor located at one of the radiating edges capacitively loads the CPA. The resonant frequency of the antenna is tuned electrostatically by applying a DC bias voltage between the MEMS varactor and the actuation pad on the antenna. The movable MEMS varactor membrane deflects downward toward the actuation pad due to an electrostatic force of attraction caused by the applied DC bias voltage. The deflection of the varactor membrane decreases the air gap, thereby increasing the loading capacitance. The increase in the loading capacitance results in a downward shift in the resonant frequency of the CPA. The CPA is center fed at the second radiating edge using a 50 Ω CPW feed line. The CPA operates in the frequency range from 5.185 to 5.545 GHz corresponding to the down and up states of the varactor. The tunable frequency range is about 360 MHz and the return loss is better than 40 dB in the entire tuning range. In this tuning range, the required DC voltage is in the range of 0–116 V.

A PWB-based MEMS switched filter bank using lumped element embedded passives

Printed wiring board (PWB)-based MEMS RF switches were developed using modified processes and similar materials as used for high density interconnect/embedded passives (HDI/EP) components. By constructing cantilever-beam electrostatic mechanisms, single-pole single throw through single-pole four-throw RF switches were developed with suitable performance in the microwave band. Combining these switches with embedded lumped element filter components using the same substrate materials, a switched filter bank was simulated, fabricated, and measured results shown.

Gigabit wireless personal area networks: Motivation, challenges and implementation

Demands in file size and transfer rates for consumer products are escalating, requiring gigabit rates for applications such as uncompressed streaming video. A number of wireless technologies are attempting to meet the gigabit-plus rates required for these applications. The most promising of these wireless solutions is found to be the use of the 60 GHz band. This technology can provide the needed bandwidth for the most demanding application - even with modest modulation and coding implementations. The objective of this work is to provide an up to date overview of gigabit wireless systems with a focus on wireless personal area networks.

PCB MEMS-Based Tunable Coplanar Patch Antenna

In this paper, a tunable coplanar rectangular patch antenna (CPA) designed using a MEMS varactor is reported. The MEMS varactor is monolithically integrated with the antenna on duroid substrate using printed circuit processing techniques. Specifically, the MEMS varactor located at one of the radiating edges capacitively loads the CPA. The resonant frequency of the antenna is tuned electrostatically by applying a DC bias voltage between the MEMS varactor and the actuation pad on the antenna. The movable MEMS varactor membrane deflects downward towards the actuation pad due to electrostatic force of attraction caused by the applied DC bias voltage. The deflection of the varactor membrane decreases the air gap thereby increasing the loading capacitance. The increase in the loading capacitance results in a downward shift in the resonant frequency of the CPA. The CPA is center fed at the second radiating edge using a 50 Omega CPW feed line. The CPA operates in the frequency range from 5.185 to 5.545 GHz corresponding to the down and up states of the varactor. The tunable frequency range is about 360 MHz and the return loss is better than 40 dB in the entire tuning range. In this tuning range, the required DC voltage is in the range of 0-116 V.

Organic MEMS devices and MWCNT (multi-wall carbon nanotube) interconnects

RF system front ends need to be mounted on a circuit board and interconnected to other devices such as antennas and surrounding circuitry functions. Providing suitable RF performing interconnects between or within devices on multi-layer construction has been done typically with doped semiconductors, copper, and occasionally other conductors. This paper discusses the use of organic printed circuit board MEMS switches and varactors, and the use of multi-wall carbon nanotubes as transmission lines and antennas. Carbon nanotube active transistors use single wall carbon nanotubes (SWCNT) with efforts to improve percentages of semiconducting structures. Interconnects are needed not only to connect CNT devices to each other, but to larger structures in order to be able to use subsystems that integrate CNT devices, large scale multifunction ICs, and RF devices used in RF front ends, including antennas. This paper addresses the use of organic substrates as the media for integration of MEMS, interconnects to devices on the substrate, and planar antennas. These methods will be required until complete assembly of all devices and interconnects can be done with processes at the nano-scale level, which is assumed to still need efficient radiative antenna structures at a larger scale for commonly used consumer wireless products.

RF‐MEMS switches on a printed circuit board platform

Purpose – The purpose of this paper is to present a new class of printed circuit board (PCB)‐based, radio frequency micro‐electro‐mechanical systems (RF‐MEMS) switches and to describe the packaging method and evaluate performance.Design/methodology/approach – Traditional PCB materials and processes were combined with photolithographic high‐density interconnect (HDI) and MEMS to form 3D high‐performance RF switches.Findings – A new type of MEMS RF switch has been developed on a PCB platform. Using processes analogous to those used for silicon MEMS, PCB, and HDI technologies were utilized to fabricate these 3D structures. The PCB‐based microstructures are “mil‐scale” rather than the “micro‐scale” of silicon MEMs. A co‐fabrication packaging method for the MEMS RF switch was also developed. The PCB‐based MEMS switches have demonstrated excellent RF performance and “hot‐switching” RF power‐handling capability. PCB‐based MEMS RF switches have the advantages of low cost and amenability to scale‐up for a high deg...