Good RF Performance Research Articles

Design of Very Compact Bandpass Filters Based on Differential Transformers

This letter presents two compact differential transformer-based bandpass filters (BPFs) using the integrated passive device technology based on a GaAs substrate. The two designs are located at the 900-MHz center frequency and have a 3 dB fractional bandwidth of 14%. Good RF performances and miniaturizations are achieved in these two designs. The measured insertion losses of the type-A and type-B filters are less than 1.25 dB and 0.8 dB, respectively. The overall size of both BPFs are especially small compared to other works, which are only 7.8×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×7.8×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> and 9.0×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×7.8×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> . The second design provides a good solution for the limitations and issues of the first proposed design. To verify the proposed design, two prototypes are implemented, and the measured results validate the correctness of the presented design approach.

A chip-on-board packaged bandpass filter using cross-coupled topological optimised hairpin resonators for X-band radar application

Devices that are compact in design and fabrication continue to draw attention for specific applications that require high performance. A compact elliptic bandpass filter using a cross-coupled topological structure with a hairpin resonator optimised for radar applications is presented in this paper. This work presents the design theory and corresponding semiconductor fabrication processes and describes the chip-on-board packaging method in detail. The proposed design of the bandpass filter can not only reduce the size of the device and result in good RF performance, but the accurate semiconductor fabrication process can also ensure high performance further. In addition, the presented chip-on-board packaging method can greatly enhance the reliability and long-term stability of a microwave device, which rarely introduces RF characteristic interference. The simulated, bare-chip measured and final chip-on-board measured results agreed well, which validated the correctness of the proposed approach.

Design of ESD Protection Diodes With Embedded SCR for Differential LNA in a 65-nm CMOS Process

The pin-to-pin electrostatic discharge (ESD) issue for a differential low-noise amplifier (LNA) was studied in this work. A new design of ESD protection diodes with an embedded silicon-controlled rectifier (SCR) was proposed to protect the gigahertz differential LNA. The proposed ESD protection design was modified from the conventional ESD protection design without adding any extra device. The SCR path was established directly from one differential input pad to the other differential input pad so the pin-to-pin ESD robustness can be improved. This design had been verified in a 65-nm CMOS process. Besides, this design had been further applied to a 24-GHz LNA in the same 65-nm CMOS process. Experimental results had shown that the proposed ESD protection design for the differential LNA can achieve excellent ESD robustness and good RF performances.

Analysis of Au metal–metal contacts in a lateral actuated RF MEMS switch

This paper reports on the ohmic contacts of an radio-frequency micro-electro-mechanical-system (RF MEMS) switch. The structure of the MEMS is described briefly to give information about the organization of the switch device. The most significant performance data are reported, indicating very low actuation voltage below 5 V, switching time of &lt;10 µs and good RF performance for frequencies up to 5 GHz. Since the contact performance is a key for excellent RF performance in the actuated state and for high reliability as well the article is focused on the contacts. It is supposed that asperities are building the current path in a closed contact, which is proved by measurements of the closing process with high time resolution. The measurements exhibit very good power-handling capabilities of the contacts. The reported findings render prior theoretical experiments with a physical device.

Low Voltage Rf Mems Capacitive Shunt Switches

Micro-electro-mechanical-systems(MEMS) switches have low resistive loss, negligible power consumption, good isolation and high power handling capability compared with semiconductor switches. Lifetime of capacitive shunt switches strongly depends on the actuation voltage so low voltage switches is necessary to enhance its performance as well as to broaden its application area. This paper presents the design and simulation of low voltage capacitive shunt MEMS switches together with its RF performance for high frequency applications. The low voltage switches are realized by lowering the spring constant of the beam using serpentine spring designs together with large capacitive area so as to achieve the good RF performance as well. The pull-in voltage is analyzed with commercial CAD finite element analysis software CoventorWare. The electromagnetic performance in terms of scattering parameters, insertion loss, and isolation are analyzed with software Ansoft HFSS10. The switches achieved insertion loss $$<$$ < 0.47 dB in on state from 2 to 40 GHz; it provided better than 25 dB isolation in off state with a capacitance ratio of 94---96. The actuation voltage as low as 1.5 V with actuation area $$110\,\times \,100\,\upmu \mathrm{m^2}$$ 110 × 100 μ m 2 along with good RF performance is reported. The design parameter optimization including selection of appropriate number of meanders and its width found to be one of the most sensitive factors affecting the spring stiffness and actuation voltage.

Rapid deposition of polycrystalline diamond film by DC arc plasma jet technique and its RF MESFETs

Diamond is a promising semiconductor material for high power, high frequency and high temperature electronic devices. High-purity polycrystalline diamond with large grain size has showed prominent RF properties. In this work, polycrystalline free-standing diamond film with grain size of 150 μm was grown by DC arc plasma jet technique with a growth speed as high as 20 μm/h. The prepared diamond sample showed high-purity with a (220) preferred orientation by the XRD and Raman spectra measurements. By a self-aligned process, hydrogen terminated p -type diamond MESFETs with gate length of 100 nm were fabricated on the 15 mm × 15 mm diamond film and showed good DC and RF performances with drain saturation current 225.7 mA/mm and maximum oscillation frequency ( f max ) 46.8 GHz. • 15 × 15 mm 2 diamond film is prepared by dc arc plasma jet method. • I DS of 225.7 mA/mm and f max of 46.8 GHz are reached.

Investigation of the Flip-Chip Package With BCB Underfill for W-Band Applications

Flip-chip package has great potential for use in millimeter-wave applications. However, the coefficient of thermal expansion mismatch between the chip and the substrate usually generates thermal stresses that fracture the flip-chip structure. The use of underfills with low dielectric loss is essential to improve the mechanical strength and reliability of the flip-chip package. Benzocyclobutene (BCB) was used in this study as the underfill material for the flip-chip structure using the no-flow process. The flip-chip structure with BCB injection provides good RF performance with a return loss of better than 18 dB and an insertion loss of 0.6 dB up to 100 GHz, in addition to a lower dielectric loss. Furthermore, thermal cycle and shear force tests show that the underfill injection can significantly improve the reliability of a flip-chip package.

Dynamic Study of a Capacitive MEMS Switch with Double Clamped-Clamped Microbeams

We study a capacitive MEMS switch composed of two clamped-clamped exible microbeams. We first develop a mathematical model for the MEMS switch where the upper microbeam represents the ground transmission line and the lower one represents the central transmission line. An electrostatic force is applied between the two microbeams to yield the switch to its ON and OFF states. We derive the equations of motion of the system and associated boundary conditions and solve the static and dynamic problems using the differential quadratic method. We show that using only nine grid points gives relatively accurate results when compared to those obtained using FEM. We also examine the transient behavior of the microswitch and obtain results indicating that subsequent reduction in actuation voltage, switching time, and power consumption are expected along with relatively good RF performances. ANSYS HFSS simulator is used in this paper to extract the RF characteristics of the microswitch. HFSS simulation results show that the insertion loss is as low as −0.31 dB and that the return loss is better than −12.41 dB at 10 GHz in the ON state. At the OFF state, the isolation is lower than −23 dB in the range of 10 to 50 GHz.

Single-Pole Double-Throw Switches for 2.4 GHz Transceiver in Wireless Communication Applications

The aim of this paper is to present several active types of compact SPDT switches operating at 2.4 GHz and then to compare and interpret the results. An active inductor loaded switch, operating at 2.4 GHz, was designed, and then this switch was simulated with AWR Microwave Office Software, using Moment Method. A 2.4-GHz single-pole double-throw (SPDT) switch with an insertion loss of −5 dB, a 2.4 GHz SPDT switch with PIN diode having an insertion loss of −6 dB and 2.4 GHz SPDT switch with GaAs FETs with an insertion loss of −5.5 dB was implemented using 8 V. The -24 dB return loss in the pass band is the best result for GaAs FETs. So SPDT switch using FET design is better for wireless communications. The other simulation performances of the switches are summarized in the list. A good RF performance has been achieved in the designed SPDT switch based on an active switch. The proposed switch could be used for 802.11b wireless local area network applications.

밀리미터파 응용을 위한 완전집적 다운컨버터 MMIC

Abstract: In this paper, we developed a fully integrated downconverter MMIC (monolithic microwave in-tegrated circuit) including Lange coupler and output active balun for millimeter wave applications. Concretely, λ/4 transmission line was added to Lange coupler for size reduction of RF/LO input, and mixed RF/LO signals were applied to gate of the FET of mixer. Active balun was used at output port for a coupling of out-of-phase IF output signals. According to measured results, the proposed down-converter MMIC showed good RF performances. For example, the downconverter MMIC showed an LO leakage power of -25 dBc at IF output port, and a RF-LO isolation of 18 dB. Therefore, off-chip com-ponents such as LO rejection filters were not required for a normal operation of the proposed down-converter MMIC. The proposed downconverter MMIC showed a conversion gain of 10.3 dB at RF fre-quency of 63 GHz. The size of the downconverter MMIC including all active and passive components was 2.2 × 1.4 mm

Highly Miniaturized 1-4 On-Chip PowerDivider/Combiner Circuit on Silicon Substrate forApplication to Long Distance Wireless PowerTransmission

In this paper, for application to a long distance wireless power transmission, a highly miniaturized 1-4 power divider/combiner employing periodic structure was fabricated on semiconducting silicon substrate. The 1-4 divider/combiner showed good RF performances from 1 to 25 GHz, and its size was 1.08 x 0.63 mm 2 , which is 0.14 % of the size of the one fabricated on PCB. Base station transmits the power needed for the operation of pilotless aircraft and satellite. In this case, a long distance wireless power transmission is required to provide the operation power for the aircraft and satellite. The long distance wireless power transmission system is shown in Fig. 2. Power source provide microwave power using oscillator for wireless transmission. The microwave power is amplified by power amplifier, and amplified microwave power is transmitted to the power consumer.

Tranceiver Mixer MMICs Employing Cascode CircuitStructure for Personal Area Network (PAN) Applications

MMIC (monolithic microwave integrated circuit) chip set was developed for application to wireless PAN. Concretely, cascade type transceiver mixers employing GaAs p-HEMT were fabricated on GaAs substrate. The mixer MMICs showed good RF performances. Concretely, the conversion gain of the receiver mixer was 9.6 dB at a LO input of 8 dBm, and 9.6 ± 1.6 dB at a RF frequency range of 62.5 - 63.5 GHz. The chip size of the receiver mixer was 2.7 mm x 1.35 mm. The conversion gain of the transmitter mixer was 6.5 dB at a LO input of 8.5 dBm, and 6.5 ± 0.25 dB at a IF frequency range of 1.9 - 2.9 GHz. The chip size of the transmitter mixer was 2.7 mm x 1.35 mm. 0.2 μm

Effect of Gate Length on Device Performances of AlSb/InAs High Electron Mobility Transistors Fabricated Using BCl3 Dry Etching

In this paper, we present the development of a mesa isolation process for AlSb/InAs high electron mobility transistors (HEMTs) using inductively coupled plasma (ICP) etching with BCl3 gas. Devices with different gate lengths (Lg: 60, 100, and 200 nm) fabricated by this dry etching technique show good DC and RF performances. With an appropriate Lg/gate-channel distance ratio, the 200-nm-gate has very high peak transconductances of 781 mS/mm at VDS = 0.1 V and 2000 mS/mm at VDS = 0.5 V. Moreover, an extrinsic current gain cutoff frequency of 137 GHz and maximum oscillation frequency of 97 GHz were achieved at a drain bias voltage VDS = 0.3 V, indicating the great potential for such a device operating at high frequency with extremely low DC power consumption.

High performance WLAN balun using integrated passive technology on SI‐GaAs substrate

AbstractAn 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 &lt; −0.25 dB and a return loss of &gt; −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

Design and testing of a 5 GHz TE10–TE30 mode converter mock-up for the lower hybrid antenna proposed for ITER

The design and overall dimensions of a 5GHz TE10–TE30 mode converter are presented. This mode converter is a RF element of a 20MW CW lower hybrid system proposed for ITER. A low power mock-up of this device has been manufactured at CEA/IRFM and measured at low power. RF measurements indicate a return loss of 40dB and a transmission loss of 4.78dB±0.03dB for the three outputs. The forward conversion efficiency from TE10 mode to TE30 has been measured from electric field probing to 99.9%. The good RF performances obtained validate the RF design of this element.

Design of millimeter-wave MEMS-based reconfigurable front-end circuits using the standard CMOS technology

This paper describes the designs of three reconfigurable CMOS-MEMS front-end components for V-/W-band applications. The suspended MEMS structure is released through post-CMOS micromachining. To achieve circuit reconfigurability, dual-state and multi-state fishbone-beam-drive actuators are proposed herein. The reconfigurable bandstop is fabricated in a 0.35 µm CMOS process with the chip size of 0.765 × 0.98 mm2, showing that the stop-band frequency can be switched from 60 to 50 GHz with 40 V actuation voltage. The measured isolation is better than 38 dB at 60 GHz and 34 dB at 50 GHz, respectively. The bandpass filter-integrated single-pole single-throw switch, using the 0.18 µm CMOS process, demonstrates that insertion loss and return loss are better than 6.2 and 15 dB from 88 to 100 GHz in the on-state, and isolation is better than 21 dB in the off-state with an actuation voltage of 51 V. The chip size is 0.7 × 1.04 mm2. The third component is a reconfigurable slot antenna fabricated in a 0.18 µm CMOS process with the chip size of 1.2 × 1.2 mm2. By utilizing the multi-state actuators, the frequencies of this antenna can be switched to 43, 47, 50.5, 54, 57.5 GHz with return loss better than 20 dB. Those circuits demonstrate good RF performance and are relatively compact by employing several size miniaturizing techniques, thereby enabling a great potential for the future single-chip transceiver.

Fabrication of 150-nm T-Gate Metamorphic AlInAs/GaInAs HEMTs on GaAs Substrates by MOCVD

Metamorphic AlInAs/GaInAs high-electron-mobility transistors (HEMTs) of 150-nm gate length with very good device performance have been grown by metal-organic chemical vapor deposition, with the introduction of an effective multistage buffering scheme. By using a combined optical and e-beam photolithography technology, submicrometer mHEMT devices have been achieved. The devices exhibit good dc and RF performance. The maximum transconductance was 1074 mS/mm. The nonalloyed ohmic contact resistance <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Rc</i> was as low as 0.02 Ω·mm. The unity current gain cutoff frequency ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">fT</i> ) and the maximum oscillation frequency ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> ) were 279 and 231 GHz, respectively. This device has the highest <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">fT</i> yet reported for 150-nm gate-length HEMTs. Also, an input capacitance to gate-drain feedback capacitance ratio <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gs</sub> / <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gd</sub> of 3.2 is obtained in the device.

Fabrication of 160-nm T-gate metamorphic AlInAs/GaInAs HEMTs on GaAs substrates by metal organic chemical vapour deposition

The fabrication and performance of 160-nm gate-length metamorphic AlInAs/GaInAs high electron mobility transistors (mHEMTs) grown on GaAs substrate by metal organic chemical vapour deposition (MOCVD) are reported. By using a novel combined optical and e-beam photolithography technology, submicron mHEMTs devices have been achieved. The devices exhibit good DC and RF performance. The maximum current density was 817 mA/mm and the maximum transconductance was 828 mS/mm. The non-alloyed Ohmic contact resistance Rc was as low as 0.02 Ω-mm. The unity current gain cut-off frequency (fT) and the maximum oscillation frequency (fmax) were 146 GHz and 189 GHz, respectively. This device has the highest fT yet reported for a 160-nm gate-length HEMTs grown by MOCVD. The output conductance is 28.9 mS/mm, which results in a large voltage gain of 28.6. Also, an input capacitance to gate-drain feedback capacitance ratio, Cgs/Cgd, of 4.3 is obtained in the device.

E-대역 상/하향 주파수 변환기용 소형 MMIC 단일 평형 다이오드 혼합기

본 논문에서는 0.1 <TEX>${\mu}M$</TEX> GaAs p-HEMT 상용 공정을 이용한 E-대역 상/하향 주파수 변환기용 소형 MMIC 단일 평형 다이오드 혼합기를 개발하였다. 본 혼합기에는 LO 발룬을 포함하며 우수한 RF 특성의 Marchand 발룬을 사용하였다. RF 포트와 IF 포트에서는 고역 통과 필터와 저역 통과 필터를 각각 사용하여 포트별 격리도를 향상시켰다. 0.58 <TEX>$mm^2$</TEX>(0.85 mm<TEX>${\times}$</TEX>0.68 mm) 칩 크기의 매우 소형으로 제작된 단일 평형 다이오드 혼합기의 측정 결과, 71～86 GHz 주파수 범위에서 10 dBm LO 입력에 대해 삽입 손실이 8～12 dB이고, 입력 P1dB가 1～5 dBm의 결과를 보였다. This paper presents a compact single balanced diode mixer fabricated using a 0.1 <TEX>${\mu}M$</TEX> GaAs p-HEMT commercial process for an E-band frequency up/down converter. This mixer includes a LO balun employing a Marchand balun with a good RF performance. In order to improve the port-to-port isolation, a high pass filter and a low pass filter are include in this mixer at the RF and IF ports, respectively. The fabricated mixer with a very compact size of 0.58 mm2(0.85 mm<TEX>${\times}$</TEX>0.68 mm) exhibits a conversion loss of 8～12 dB and an input P1dB of 1～5 dBm at the LO power of 10 dBm from 71～86 GHz.

Self-Consistent Subband Calculations of Al&lt;sub&gt;x&lt;/sub&gt;Ga&lt;sub&gt;1-x&lt;/sub&gt;N/(AlN)/GaN-Based High Electron Mobility Transistor

In this paper, there is an attempt to present the two dimensional electron gas (2DEG) transport characteristics of AlxGa1-xN/(AlN)/GaN-based High Electron Mobility Transistor (HEMT) using a self-consistent numerical method for calculating the conduction-band profile and subband structure. The subband calculations take into account the piezoelectric and spontaneous polarization effects and the Hartree and exchange-correlation interaction. Here the dependency of conduction band profile, subband energies, 2DEG sheet concentration and sheet resistance on various Al mole fractions of AlxGa1-xN barrier layer are presented by incorporating simulation as well as available experimental data. Introduction of very thin binary AlN layer at the heterojunction of AlxGa1-xN/GaN resulting high mobility at high sheet charge densities by increasing the effective and decreasing alloy disorder scattering. Devices based on this structure exhibit good DC and RF performance as an increase of . Owing to high 2DEG density , the proposed device leads to operate in microwave and millimeter wave applications.