Design and development of broadband gap waveguide-based 0-dB couplers for Ka-band applications

The design and fabrication of a wideband millimetre-wave 0-dB coupler is proposed in this paper using gap waveguide technology for low-loss and high-power applications in 30-GHz frequency band. To overcome the fabrication challenges in millimetre-wave frequencies, the gap waveguide technique is utilised. Two gap waveguide-based coaxial- and waveguide-fed 0-dB couplers are designed with broadband performance, high return loss, acceptable coupling flatness and high isolation. For verifying the performance of the proposed structures, a prototype of the waveguide-fed 0-dB coupler is manufactured and measured. The measurement results show that the return and insertion losses and the isolation of the fabricated 0-dB coupler is better than 18 dB, 0.5 and 18 dB, respectively, in the specified frequency range from 26.2 to 34 GHz. Moreover, the breakdown power level of the proposed millimetre-wave structures is in kW orders to satisfy the high-power requirements

Multi-Port RF MEMS Switches and Switch Matrices

Microwave and millimeter wave switch matrices are essential components in telecommunication systems. These matrices enhance satellite capacity by providing full and flexible interconnectivity between the received and transmitted signals and facilitate optimum utilization of system bandwidth. Waveguide and semiconductor technology are two prominent candidates for the realizing such types of switch matrices. Waveguide switches are dominant in high frequency applications of 100 ? 200 GHz and in high power satellite communication. However, their heavy and bulky profile reinforces the need for a replacement. In some applications, semiconductor switches are an alternative to mechanical waveguide switches and utilize PIN diodes to create the ON and OFF states. Although, these switches are small in size, they exhibit poor RF performance and low power handling. RF MEMS technology is a good candidate to replace the conventional switches and to realize an entire switch matrix. This technology has a great potential to offer superior RF performance with miniaturized dimensions. Because of the advantages of MEMS technology numerous research studies have been devoted to develop RF MEMS switches. However, they are mostly concentrated on Single-Pole Single-Throw (SPST) configurations and very limited work has been performed on MEMS multi-port switches and switch matrices. Here, this research has been dedicated on developing multi-port RF MEMS switches and amenable interconnect networks for switch matrix applications. To explore the topic, three tasks are considered: planar (2D) multi-port RF MEMS switches, 3D multi-port RF MEMS switches, and RF MEMS switch matrix integration. One key objective of this thesis is to investigate novel configurations for planar multi-port (SPNT), C-type, and R-type switches. Such switches represent the basic building blocks of switch matrices operating at microwave frequencies. An in house monolithic fabrication process dedicated to electrostatic multi-port RF MEMS switches is developed and fine tuned. The measurement results exhibit an excellent RF performance verifying the concept. Also, thermally actuated multi-port switches for satellite applications are designed and analyzed. The switch performance at room condition as well as at a very low temperature of 77K degrees (to resemble the harsh environment of satellite applications) is measured and discussed in detail. For the first time, a new category of 3D RF MEMS switches is introduced to the MEMS community. These switches are not only extremely useful for high power applications but also have a great potential for high frequencies and millimetre-waves. The concept is based on the integration of vertically actuated MEMS actuators inside 3D transmission lines such as waveguides and coaxial lines. An SPST and C-type switches based on the integration of rotary thermal and electrostatic actuators are designed and realized. The concept is verified for the frequencies up to 30GHz with measured results. A high power test analysis and measurement data indicates no major change in performance as high as 13W. The monolithic integration of the RF MEMS switch matrix involves the design and optimization of a unique interconnect network which is amenable to the MEMS fabrication process. While the switches and interconnect lines are fabricated on the front side, taking advantage of the back side patterning provides a high isolation for cross over junctions. Two different techniques are adopted to optimize the interconnect network. They are based on vertical three-via interconnects and electromagnetically coupled junctions. The data illustrates that for a return loss of less than -20dB up to 30GHz, an isolation of better than 40dB is obtained. This technique not only eliminates the need for expensive multilayer manufacturing process such as Low Temperature Co-fired Ceramics (LTCC) but also provides a unique approach to fabricate the entire switch matrix monolithically

A COMPREHENSIVE OVERVIEW OF RECENT DEVELOPMENTS IN RF-MEMS TECHNOLOGY-BASED HIGH-PERFORMANCE PASSIVE COMPONENTS FOR APPLICATIONS IN THE 5G AND FUTURE TELECOMMUNICATIONS SCENARIOS

The goal of this work is to provide an overview about the current development of radio-frequency microelectromechanical systems technology, with special attention towards those passive components bearing significant application potential in the currently developing 5G paradigm. Due to the required capabilities of such communication standard in terms of high data rates, extended allocated spectrum, use of massive MIMO (Multiple-Input-Multiple-Output) systems, beam steering and beam forming, the focus will be on devices like switches, phase shifters, attenuators, filters, and their packaging/integration. For each of the previous topics, several valuable contributions appeared in the last decade, underlining the improvements produced in the state of the art and the chance for RF-MEMS technology to play a prominent role in the actual implementation of the 5G infrastructure

Radiowave propagation and antennas for high data rate mobile communications in the 60 GHz band

The 60 GHz MIMO systems are seen as some of the best candidates for the implementation of future high data-rate short range communications systems such as wireless personal area networks (WPAN). Although the performance of MIMO systems has been studied thoroughly theoretically and experimentally at lower frequencies like at 2 and 5 GHz, there is a clear lack of measurement data and experimental performance evaluations of MIMO techniques at 60 GHz. Furthermore, more effort is still needed in the design and evaluation of compact low cost 60 GHz antennas for communication applications. In the first part of the thesis, the first 60 GHz MIMO channel measurement system is presented. It is based on a previously developed 2 and 5 GHz sounder and frequency converters. This system uses virtual antenna arrays to create the channel matrix. A measurement campaign is reported. In order to improve the delay resolution, two other MIMO measurement systems are presented, based on an ultra wide band (UWB) sounder and a vector network analyzer (VNA). Those systems allow full characterization of the MIMO channel in the delay and angular domains. In the second part of this work, the performance of multi-antenna techniques is evaluated based on the measurement data obtained in the first part of the thesis. Three of the most promising multi-antenna techniques, namely MIMO, antenna selection MIMO, and beam steering, are analyzed and compared. The presented results indicate that the mutual information of the measured MIMO channel is quite close to that of the independent and identically distributed (i.i.d.) MIMO Rayleigh channel. Furthermore, in realistic conditions it is seen that MIMO-antenna selection often leads to lower mutual information than traditional MIMO with the same number of RF chains. Moreover, it is shown that when considering phase shifters with realistic losses, MIMO technique almost always outperforms beam steering technique. In the last part of the thesis a 60 GHz planar omnidirectional antenna is presented. This antenna is very suitable for communications applications since it has low profile and uses a metal layer only on one side of the substrate. Therefore, it can be manufactured easily and at very low cost. In addition, an advanced quasi full 3-D radiation pattern measurement system has been developed to evaluate probe-fed antennas. Very good measurement repeatability is reported. The radiation of the probe is analyzed and is seen to be the main limitation of the dynamic range of the measurement setup

Wireless Applications of Radio Frequency Micro-Electro-Mechanical Systems

With mass proliferation of wireless communication technologies, there is a continuous demand on fast data transmission rate and efficient use of frequency spectrum. As a result, reconfigurable systems are of significant importance and research is being conducted in numerous universities. The purpose of this research is to develop novel RF MEMS based reconfigurable wireless systems. By utilizing the RF MEMS switches as a basic building block, this thesis focus on developing a unique design technique for the design and development of RF MEMS delay line phase shifter, frequency reconfigurable antennas and pattern reconfigurable antennas. This thesis work is divided into four parts: 1. Investigation and development of nano-electro-mechanical systems (NEMS) based 3-bit phase shifter. Analyzing the slow wave structure to further reduce the size of delay line phase shifter. 2. Development of frequency reconfigurable antennas to compete with broadband and multi-band antennas. Two novel MEMS-loaded frequency reconfigurable antennas were designed with spectrum switchable between WPAN band (57 to 66 GHz) and the whole E-band (71 to 86 GHz). 3. Investigation of microstrip-to-coplanar striplines (CPS) transition balun used for antennas to explain the inherent phase delay of this type of structure. Based on the discovery, a pattern reconfigurable quasi-Yagi antenna was designed. The antenna exhibits excellent RF performance, compact size and switchable end-fire radiation pattern with the goal to replacing existing phased array antennas. It has the full functionality of a multi-antenna phased array plus phase shifting network while its size is same as a fixed single Yagi antenna. 4. Development of full seven masks all metal fabrication process of the RF MEMS integrated reconfigurable antennas. The fabrication processes are optimized based on Australian National Fabrication Facility (ANFF) New South Wales node’s equipment

Design of antenna array and data streaming platform for low-cost smart antenna systems

The wide range of wireless infrastructures such as cellular base stations, wireless hotspots, roadside infrastructures, and wireless mobile infrastructures have been increasing rapidly over the past decades. In the transportation sector, wireless technology refreshes require constantly introducing newer wireless standards into the existing wireless infrastructure. Different wireless standards are expected to co-exist, and the air space congestion worsens if the wireless devices are operating in different wireless standards, where collision avoidance and transmission time synchronisation become complex and almost impossible. Huge challenges are expected such as operation constraints, cross-system interference, and air space congestion. Future proof and scalable smart wireless infrastructures are crucial to harmonise the un-coordinated wireless infrastructures and improve the performance, reliability, and availably of the wireless networks. This thesis presents the detailed design of a novel pre-configurable smart antenna system and its sub-system including antenna element, antenna array, and radio frequency (RF) frontend. Three types of 90° beamforming antenna array (with low, middle and high gain) were designed, simulated, and experimentally evaluated. The RF frontend module or transmit and receive (T/R) module was designed and fabricated. The performance of the T/R module was characterised and calibrated using the recursive calibration method, and drastic sidelobe level (SLL) improvement was achieved using the amplitude distribution technique. Finally, the antenna arrays and T/R modules are integrated into the pre-configurable smart antenna system, the beam steering performance is experimentally evaluated and presented in this thesis. With the combination of practical know-how and theoretical estimation, the thesis highlights how the modern smart antenna techniques that support most cutting-edge wireless technology can be adopted into the existing infrastructure with minimum distraction to the existing systems. This is in line with the global Smart City initiative, where a huge number of Internet of Things (IoT) devices being wired, or wireless are expected to work harmoniously in the same premises. The concept of the pre-configurable smart antenna system presented in this thesis is set to deliver a future-proof and highly scalable and sustainable infrastructure in the transportation market

SiGe/CMOS Millimeter-Wave Integrated Circuits and Wafer-Scale Packaging for Phased Array Systems.

Phased array systems have been used to achieve electronic beam control and fast beam scanning. In the RF-phase shifting architecture, T/R modules are required for each antenna element, and have been traditionally developed using GaAs or InP technology. This thesis demonstrates that Ka-band (35 GHz) T/R modules can also be developed using the SiGe BiCMOS technology. The designed circuit blocks include a low noise amplifier, a 4-bit phase shifter, a variable gain amplifier/attenuator, and SPDT switches. The Ka-band phase shifters are designed based on CMOS switch and miniature low-pass networks for a single-ended and differential applications, and result in 3-degree rms phase error at 35 GHz. The SiGe LNA results in a peak gain of 24 dB and a noise figure of 2.9-3.1 dB with 11 mW power consumption. The CMOS variablestep attenuator has 12-dB attenuation range (1 dB step) with very low loss and phase imbalance at 10-50 GHz. A variable gain LNA is also demonstrated at 30-40 GHz for the differential phased array receiver, and has 20-dB gain and <1-degree rms phase imbalance between the 8 different gain states and 10 dB gain control. All of these circuits show state-of-the-art performance, and the phase shifter, distributed attenuator and VGA are also first-time demonstrations at Ka-band frequencies. These circuit blocks were used in a miniature SiGe/CMOS Ka-band T/R module with a dimension of 0.93x1.33mm2, and a measured performance of 19 dB receive gain, 4-5 dB NF, 9 dB transmit gain and +5.5 dBm output P1dB. The T/R module also has 4-bit phase control and 10 dB gain control in both the transmit and receive modes. To our knowledge, this is the first demonstration of a Ka-band SiGe/CMOS T/R module to-date. Finally, a DC-110 GHz Si wafer-scale packaging technique has been developed using thermo-compression bonding and is suitable for Ka-band and even W-band T/R modules. The package transition has an insertion loss of 0.1-0.26 dB at 30-110 GHz, and the package resonances and leakage were drastically reduced by grounding the sealing ring. This is the first demonstration of a wideband resonance-free (DC-110 GHz) package using silicon technology.Ph.D.Electrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/58380/1/bmin_1.pd

Design and fabrication of low-loss RF MEMS silicon switch using glass reflow

학위논문 (석사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2013. 8. 김용권.본 연구에서는 처음으로 유리를 스위치 구조재의 일부로 사용한 저손실 RF MEMS 실리콘 스위치를 제안하였다. 기존의 실리콘만을 구조재로 사용하여 제작되었던 RF MEMS 실리콘 스위치에서 접촉 금속 부근 구조재를 유리로 대체한 새로운 형태의 RF MEMS 실리콘 스위치를 본 연구를 통해 설계 및 제작하였으며, 접촉 금속 부근의 구조재로 실리콘보다 RF 특성에 적합한 유리를 사용함으로써 향상되는 신호 손실 특성을 이론적인 분석과 시뮬레이션을 통해 예측하고, 이를 측정 결과와 비교하였다. 제안된 유리가 구조재로 삽입된 실리콘 스위치는 5 ~ 30 GHz 의 주파수 대역의 신호에 대해 0.12 ~ 0.33 dB 수준의 삽입 손실을 보여 기존의 실리콘 스위치보다 최대 0.26 dB (0.38 ~ 0.54 dB), 그리고 고저항 실리콘을 구조재로 사용한 스위치보다 최대 0.19 dB (0.31 ~ 0.46 dB) 정도 삽입 손실이 향상된 결과를 보였다. 본 연구에서 제안하는 새로운 형태의 RF MEMS 실리콘 스위치의 제작은 유리 재용융 (Glass reflow) 공정을 기반으로 한 SiOG (Silicon On Glass) 공정으로 제안되었으며, 제안된 공정을 통해 유리 구조재가 삽입된 스위치를 성공적으로 제작하고, 스위치의 정상적인 정전 구동을 확인함으로써 제안된 공정의 유효성을 검증하였다. 한편, 낮은 삽입 손실을 가지는 RF MEMS 스위치는 실제 RF 응용에 사용될 경우 시스템에서 신호 손실 및 왜곡을 보상하기 위한 추가 회로를 줄일 수 있도록 하여 시스템의 복잡도와 비용을 줄이는 동시에 시스템의 크기도 줄일 수 있는 장점과 직결된다. 또한, 보다 낮은 손실을 가지는 RF MEMS 스위치의 개발은 기지국 안테나나 방위 체계 산업, 인공위성 교환망 등과 같이 엄격한 성능 요구 조건을 가지는 고주파 응용 분야들로의 RF MEMS 스위치 적용을 촉진시킬 것으로 기대된다. 따라서, 저손실 RF MEMS 스위치의 개발은 다양한 RF 응용에서 RF MEMS 스위치의 활용도를 높이는 데 이바지할 수 있다.In this paper, we firstly propose a novel low-loss RF MEMS silicon switch which utilizes reflowed glass as a switch structure near the contact metal. A new concept of electrostatically-driven RF MEMS silicon switch was presented and realized through the proposed fabrication process. By introducing reflowed glass into the silicon switch structure, the substrate loss induced by switch structure has greatly reduced. To verify the enhancement in loss characteristic, we fabricated 3 different types of RF MEMS silicon switches (silicon-, high resistance silicon-structured switch, and the proposed switch) and measured their insertion losses. In the frequency range of 5 to 30 GHz, the proposed RF MEMS switch with reflowed glass inside the switch structure showed insertion loss of 0.12 ~ 0.33 dB, while silicon- and high resistance silicon-structure switch showed 0.38 ~ 0.54 dB, 0.31 ~ 0.46 dB, respectively. Before fabrication, theoretical analysis and simulations were carried out to predict the enhancement in insertion loss brought by the introduction of the reflowed glass. The expected improvement in the insertion loss characteristic of proposed RF MEMS switch was greater than 0.1 dB, compared to the conventional RF MEMS silicon switch. Proposed fabrication method of the novel RF MEMS switch was based on SiOG process, assisted with the glass reflow process. The proposed fabrication process was validated with successful fabrication of the proposed switch. We believe that the proposed fabrication process could be used for a wide range of RF MEMS area where low-loss characteristic is needed. Low insertion loss characteristic of RF MEMS switch can contribute to reduce not only the complexity and cost, but also the size of the system by eliminating additional circuitry for loss compensation in the system. Therefore, it can be said that development of low loss RF MEMS switch can widen RF application fields where RF MEMS switch can be used. Furthermore, with this enhanced loss characteristic, RF MEMS silicon switch is expected to be used in the RF applications of strict performance requirement, such as base-station antenna, defense system, satellite switching network, etc.초록 i 목차 iii 표 목차 v 그림 목차 vi 제 1 장 서론 １ 1.1 연구의 배경 １ 1.2 RF MEMS 스위치의 연구 동향 ４ 1.2.1 RF MEMS 스위치 ４ 1.2.2 RF MEMS 스위치의 응용 분야 ８ 1.3 연구의 동기 및 목적 １２ 1.4 논문의 구성 １４ 제 2 장 유리 재용융 공정을 이용한 저손실 RF MEMS 실리콘 스위치의 이론과 설계 １６ 2.1 RF MEMS 실리콘 스위치가 제작된 CPW 전송 선로의 기판 손실 분석 １６ 2.2 CPW 전송 선로의 설계 ２２ 2.3 스위치 구조의 설계 ２７ 2.3.1 스위치의 접촉부 영역 설계 ２７ 2.3.2 스위치 구조물 및 스프링의 설계 ２９ 2.3.3 스위치의 구동 전압 특성 예측 ３１ 2.3.4 스위치의 신호 전송 특성 예측 ３５ 제 3 장 유리 재용융 공정을 이용한 저손실 RF MEMS 실리콘 스위치의 제작 ３８ 3.1 전체 제작 과정 ３８ 3.2 단위 공정 ３９ 3.2.1 유리 재용융을 이용한 실리콘 기판의 제작 ３９ 3.2.2 CPW 전송 선로 제작을 위한 유리 기판의 제작 ４９ 3.2.3 실리콘-유리 기판의 접합 및 Release 공정 ５７ 3.3 제작 결과 ６０ 제 4 장 유리 재용융 공정을 이용한 저손실 RF MEMS 실리콘 스위치의 특성 측정 ６５ 4.1 스위치 구동 전압 특성 측정 ６５ 4.2 스위치 신호 전송 특성 측정 ６９ 제 5 장 결론 ７６ 참고문헌 ７８ ABSTRACT ８２Maste

Tuneable RF MEMS components using SU-8

With the rapid progress in the wireless communication field, radio frequency microelectro- mechanical systems (RF MEMS) are seen as one of the promising technologies to replace the existing high power communication systems. MEMS based tuneable devices such as varactors and phase shifters offer many advantages over their conventional diode-based counterparts including low loss, low power consumption and high linearity. MEMS varactors in particular can be integrated into many reconfigurable modules such as switching and reconfigurable matching networks. Moreover, distributed MEMS transmission line (DMTL) phase shifters with their linear phase characteristic can be applied to wideband phased array antennas for microwave medical imaging which requires beam steering and high gain antenna systems. This thesis focuses on the design and development of two RF MEMS devices which are a high tuning ratio digital MEMS varactor and a low frequency DMTL phase shifter using SU-8 polymer. The design and simulation of a 4-bit and a 5-bit digital MEMS varactors have been carried out in the first phase of this study. One of the limitations of the digital MEMS varactors fabricated on silicon substrates is the high fringing field capacitance that reduces the overall capacitance ratios of the devices. To reduce the effect of the fringing fields, two methods have been proposed to elevate the varactors from the silicon substrate. In the first method, a 26.35 μm deep trench is etched in the silicon substrate under the 4-bit digital MEMS varactor which is able to achieve a high capacitance ratio of 35.7. In the 5-bit digital MEMS varactor design, SU-8 material is used to form a 20 μm thick separation layer between the varactor and the silicon substrate instead of the deep trench method applied in the 4-bit MEMS varactor. The simulated capacitance ratio of the 5-bit digital MEMS varactor is 34.8. Additionally, the SU-8 also serves as a sacrificial layer to release the MEMS bridges on the devices hence reducing the fabrication process compared to the conventional MEMS release process that uses oxide as the sacrificial material. To verify the performance of using the thick SU-8 dielectric layer in reducing the fringing field capacitance in the varactor design, single-bridge varactors with different lengths and widths have been fabricated and analysed. A novel truss bridge structure has been proposed in order to reduce the pull-in voltage of the varactors. It is found that by using the truss structure, the measured pull-in voltage of the bridge can be reduced by 12.5% compared to the conventional solid fixed-fixed bridge structure. However, due to the high residual stress from the fabrication process which causes the bridge to warp over its width, the achievable average down-state capacitance of the fabricated single-bridge varactor is limited to 211 fF compared to the simulated value of 1.28 pF. Nevertheless, the capacitance ratio of the device fabricated on the SU-8 layer increases by 56.75% over a similar device fabricated without the polymer which proves that the fringing field capacitance has been reduced. Furthermore, fabrication of the single-bridge MEMS varactors on low-resistivity silicon has been carried out with the use of SU-8 as the passivation layer without affecting the performances of the varactors. This finding can lead to the realisation of low-cost MEMS varactors in the future. The second part of this thesis investigates the development of distributed MEMS transmission line (DMTL) phase shifters for operation in the frequency range of 2 GHz to 4 GHz (S-band). The proposed phase shifters are a 2-bit and 3-bit digital DMTL phase shifters. One of the potential applications of the proposed phase shifters is for phased array antenna systems for microwave head imaging that requires wideband performance. The 2-bit and 3-bit DMTL phase shifters have been designed and simulated with 41 MEMS bridges and 105 MEMS bridges respectively. The simulated phase shifts of the 2-bit phase shifter design are 00, 900, 1800 and 2700 whereas for the 3-bit phase shifter, 8 phase shifts have been achieved namely 00, 450, 900, 1350, 1800, 2250, 2700 and 3150. To validate the performance of the proposed low frequency DMTL phase shifter, the 2-bit phase shifter design has been fabricated and analysed. The measured impedance matching of the phase shifter shows good performance with reflection coefficients of less than -10 dB across the operating frequency range for all the states of the phase shifter. The measured differential phase shifts of the device are 00, 17.890, 34.510 and 52.390. The lower measured differential phase shifts compared to the simulated values can be attributed to the warping of the bridges over their width which causes a formation of an air gap between the bridge and dielectric layer hence reducing the down-state capacitance of the varactors in the phase shifter. Nevertheless, this is the first DMTL phase shifter to achieve a maximum differential phase shift of 52.390 at 2.45 GHz. Based on the measured differential phase shifts, the phase shifter can provide a maximum steering angle of ±5.730 for a 4-element phased array antenna at 2.45 GHz. The maximum measured transmission loss of the phase shifter is -10.51 dB at 2.45 GHz. The high loss of the phase shifter is due to the skin depth effect since the co-planar waveguide (CPW) transmission line of the phase shifter is fabricated using 300 nm thick aluminium. Therefore, further investigation has been carried out to provide better estimation of the transmission loss of the phase shifter by fabricating a CPW transmission line with the same configuration to that of the transmission line in the fabricated phase shifter by using 2 μm thick aluminium. The measured loss of the transmission line is -2.39 dB which shows significant improvement over the loss obtained from the phase shifter. Moreover, several CPW transmission lines with different centre conductor’s widths have been fabricated and analysed to further reduce the losses of the transmission lines. An attenuation loss of only 0.122 dB/cm has been achieved using a 500 μm-width centre conductor in the fabricated CPW transmission line which can lead to the realisation of a low-loss DMTL phase shifter for low microwave frequency range. The characterisation and optimisation of the varactors and phase shifters using SU-8 provide the initial step towards the development of tuneable RF MEMS devices for wide range of applications including wireless communications and radar systems. Moreover, the proposed DMTL phase shifters for operation at the lower end of microwave spectrum particularly in the frequency range of 2 GHz to 4 GHz are vital for the realisation of wideband phased array antennas for microwave medical imaging applications

Integrated MEMS-Based Phase Shifters

Multilayer microwave circuit processing technology is essential in developing more compact radio frequency (RF) electronically scanned arrays (ESAs) for next generation radar systems. ESAs are typically realized using the hybrid connection of four discrete components: RF manifold, phase shifters or Butler matrices, antennas and T/R modules. The hybrid connection of these components increases the system size, packaging cost and introduces parasitic effects that lead to higher losses. In order to eliminate these drawbacks, there is a need to integrate these components on the same substrate, forming a monolithic phased array. RF MEMS technology enables the monolithic integration of the ESA components into one highly integrated multifunctional module, thereby enhancing ESA designs by significantly reducing size, fabrication cost and interconnection losses. A novel capacitive dual-warped beam shunt MEMS switch is presented that utilizes warped beams to enhance its RF performance. This switch exhibits an off-to-on capacitive ratio of almost 170, isolation better than 40dB, switching speeds as low as 6μs without the need for thin dielectrics or high dielectric constant materials. These MEMS switches are implemented into single pole three throw (SP3T) and single pole four throw (SP4T) configurations. A novel 3-bit finite ground coplanar waveguide switched delay line MEMS phase shifter is developed with four cascaded SP3T dual-warped beam capacitive switches to achieve low-loss performance and simplify ESA design. The fabricated prototype unit exhibits an insertion loss of 2.5∓0.2dB with a phase error of ∓6°. Moreover, a compact 4 x 4 Butler matrix switchable with the use of a MEMS SP4T switch is investigated as an alternative passive beamforming method. The overall beam-switching network is monolithically integrated within a real-estate area of 0.49cm2. This technique provides a unique approach to fabricate the entire beamforming network monolithically. An 8-mask fabrication process is developed that monolithically integrates the MEMS phase shifter and RF combining network on one substrate. The wafer-scale integrated ESA prototype unit has an area of 2.2cm2. It serves as the basic building block to construct larger scanning array modules and introduces a new level of functionality previously achieved only by the use of larger, heavier and expensive system