A Sub-THz Waveguide Magic-T With Coplanar Ports for Power Combination Applications

A Ku band dual-mode solid state power amplifier with high output power of 7W was introduced. The solid state power amplifier was composed of the power module and the RF(Raido Frequency) amplifier module. And RF amplifier module include in two channel microwave modules which possesses good performance of high output 38.45 dBm. with wide bandwidth about 150MHz, high gain stability 0.5dB.The solid state power amplifier was fabricated in a single package occupying area of 210mm*163mm*92mm.The weight of the solid state power amplifier is 2.5kg. In this paper, the design, simulation, test of performance and environmental suitability of the solid state power amplifier were discussed.

산악지형이 많은 한국 실정에서 국지적으로 발생하는 기상자료를 제공하기 위하여 진공관식 레이더 보다는 반도체를 이용한 소형의 X-band 기상레이더의 필요성이 요구되고 있다. 기상레이더의 이중 편파방식에 사용되는 반도체형 전력증폭기(SSPA)는 다수의 소출력 전력소자를 병렬로 결합함으로써 원하는 고출력을 얻을 수 있다. 이와 같이 고출력 전력증폭기에 적용되는 전력결합기는 경로손실, 고주파수, 고출력에 따른 안정저항의 문제, 열방출 특성을 해결하기 위하여 본 논문에서는 변형된 Gysel 전력결합기를 적용한 결과 격리도(isolation)의 우수성을 제시하였으며, 최대출력 54dBm, 25%의 효율을 갖는 기상레이더용 X-band 250W 급 반도체형 전력증폭기를 설계하였다. Necessity of compact X-band solid-state weather radar is required to provide weather data, which generate locally in a lot of Korea's mountainous area, rather than tube-type radar. Solid State Power Amplifier (SSPA) for using Dual-polarization method in weather radar is able to obtain desired high output by combining many low output power devices in parallel. Thus, Power combiner applying to high-output power amplifier has disadvantages such as path loss, ballast resistance problem by high frequency and high power, heat release. Therefore, In this paper we demonstrated the excellence of isolation, which is the result from modified Gysel power combiner. As a result, we designed X-band 250W solid state power amplifier with peak power 54dBm, 25% power efficiency for weather radar.

According to the requirement of X-band vertical pointing radar, this paper details design and implementation of a X-band solid-state power amplifier module by using an eight-way radial waveguide spatial power combiner structure. This radial waveguide spatial combiner is simulated and optimized by electromagnetic simulation software, and the simulation results show that, between 9.3GHz~9.5GHz, the insertion losses are below 0.1dB, the differences of phase between each port are within 0.5°. According to final optimization parameters, this radial waveguide spatial combiner is made of aluminum blanks, and assembled with eight power amplifiers. The measured insert loss of radial waveguide spatial combiner module is below 0.65dB, and the VSWR at each port are below 1.5:1. At 9.3GHz ~9.5 GHz, the measured gain of X-band power amplifier is greater than 35dB with ripple is less than 1dB, and the output power at P-1dB is greater than 15W. The average power combining efficiency of this SSPA module is greater than 85%.

A new super-thin power amplifier (PA) module has been developed for W-CDMA mobile handsets. The PA module consists of an InGaP/GaAs HBT MMIC and a 50-Ω output matching circuit on polyimide film, which is the first application of such film as a PA module substrate. The key features of the PA substrate are thinness, low thermal resistance, and low cost. As a result, the PA module is only 6.0 x 6.0 x 0.8 mm3 (0.03cc) and meets the specifications of W-CDMA with a high power-added efficiency (PAE) of 43%, a gain of 27 dB, and an adjacent channel leakage power ratio (ACLR) of -36 dBc at an offset frequency of 5 MHz at a Pout of 26 dBm under a supply voltage of 3.5 V with 3.84 Mcps HPSK modulation.

A Linearized Solid State Power Amplifier (SSPA) applying the PAMELA principle [1] has been designed and realized at Ku-Band frequencies. PAMELA stands for Power Amplifier Module for highly Efficient and highly Linear Applications. The principle utilizes an adaptive loading technique developed by DASA. The SSPA, which applies European semiconductor devices, is foreseen for active array antennas for space and terrestrial systems. In order to meet the system requirements of an array antenna, the main design drivers have been high efficiency, good linearity and close tracking between units over a wide frequency and power range. Small size, also a prerequisite for an array antenna, has been considered in the design. The power amplifier offers 2 Watts of output power when operated under multicarrier conditions. The corresponding noise power ratio is typical 20 dB. DC to RF conversion efficiency is better than 22 % with an associated gain of 33.5 dB.

Effect of voids on thermomechanical cracking in lead-free Sn3Ag0.5Cu interconnections of power modules

In this paper, the reliability of RF power transistors’ solder attachments is characterized through experiments and simulations. Test cases consisted of power amplifier (PA) modules on AlSi10Mg substrates with either a low or high mutual thermal mismatch. The module’s flange interconnections were stressed by means of thermal cycling testing (TCT) in the 15 °C–95 °C range. Scanning acoustic microscopy (SAM) was used intermittently to inspect the interconnections of selected structures during cycling breaks. Optical cross-polarization microscopy and scanning electron microscopy were used in the failure analysis of the solder joints. Different materials and dimensional variations were tested in simulations to observe differences in thermal stress. The viscoplastic behavior of lead-free solder in the interconnection was modeled using Anand’s constitutive equations. The first cracks could be observed with SAM after 100 cycles. SAM imaging showed that in the worst case, 72% of the interconnection area had cracked at the end of the 1100-cycle TCT. Only a marginal amount of cracks could be observed in PA modules with a better coefficients of thermal expansion match to the substrate. Simulations indicated that it is possible to decrease creep energies significantly and thereby increase the lifetime expectancy of interconnections by selecting the correct materials and structures.

A X-band active phased array antenna(APAA) system for satellite applications was developed and manufactured for commercial and military use. This system tracks satellite by using electronic beam-forming technology in elevation and azimuth direction. And mechanical operation was adopted in azimuth. This paper describes the architecture of this system, especially T/RX channel design, and details measured results of channel performances. In this system, TX-channel is primarily composed of active channel blocks(ACB) for transmit beam control and power amplification, multi-way power dividers and solid-state power amplifier(SSPA) having 50-Watt output power. And, RX-channel is composed of ACBs for receive beam control and low noise amplification, power combiners and beam forming blocks(BFB) for tracking beam control. Lastly, to confirm the system performances of APAA including the T/RX channel, communication test accomplished in the open air, and the result of it is presented.

A new power amplifier module (PAM) in which GaAs power MESFETs are mounted directly on an aluminum nitride (AIN) substrate has been developed for analog cellular phones. This module occupies a volume of 0.2cc, only 1/4 as large as that of conventional one, and can deliver an output power (Pout) of 31dBm with a power-added efficiency (PAE) of 58% at a low operating voltage of 3.5V around 900MHz band. Furthermore, a new microwave probe card has been introduced into on-wafer RF power measurement of the FETs in order to improve the yield of the PAMs. Using this probe card, the maximum output power of 30.9dBm has been obtained, and gain deviation between on-wafer and packaged FETs is only 1.4dB. This new concept PAM and the developed on-wafer measurement technique must promise advanced high-performance PAM.

In this article, in order to enhance the linearity of power amplifier modules (PAM), we have suppressed the harmonics at the output port of a high‐power amplifier (HPA) and cancelled the third‐order intermodulation distortion (third IMD) by a predistortion scheme. The matching network to suppress the harmonics consists of metamaterial like the composite right/left‐handed structure. Both the second and third harmonics are suppressed over 27 dBc. A phase of generated third IMD at the output of the drive amplifier has changed in order to offset the third IMD of HPA. The harmonics of the proposed PAM suppresses over 6 dB more than a single HPA and over 20 dB more than a reference power amplifier. The PAM has 37 dBm of output power and 21.6 dB of power gain. The second harmonic and third IMD are −53 and −42.5 dBc about PAM, respectively. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1497–1500, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27625

A compact power amplifier module (PAM) integrated with a power detector utilizing low temperature co-fired ceramic (LTCC) technology is presented for the IEEE 802.11a/b/g, GPRS and WCDMA applications. All MMICs' matching circuits were fabricated with the input and inter-stage matching circuits realized on-chip so that the PAM size is significantly reduced. The output matching circuit was implemented on an LTCC substrate to reduce power loss based on the advantages of high-Q ceramic components. The proposed PAM provides high power added efficiency and good linearity. Moreover, the measured results indicate the excellent performance of this PAM

BackgroundEarly identification of autism spectrum disorder (ASD) provides an opportunity for early intervention and improved developmental outcomes. The use of electroencephalography (EEG) in infancy has shown promise in predicting later ASD diagnoses and in identifying neural mechanisms underlying the disorder. Given the high co-morbidity with language impairment, we and others have speculated that infants who are later diagnosed with ASD have altered language learning, including phoneme discrimination. Phoneme learning occurs rapidly in infancy, so altered neural substrates during the first year of life may serve as early, accurate indicators of later autism diagnosis.MethodsUsing EEG data collected at two different ages during a passive phoneme task in infants with high familial risk for ASD, we compared the predictive accuracy of a combination of feature selection and machine learning models at 6 months (during native phoneme learning) and 12 months (after native phoneme learning), and we identified a single model with strong predictive accuracy (100%) for both ages. Samples at both ages were matched in size and diagnoses (n = 14 with later ASD; n = 40 without ASD). Features included a combination of power and nonlinear measures across the 10‑20 montage electrodes and 6 frequency bands. Predictive features at each age were compared both by feature characteristics and EEG scalp location. Additional prediction analyses were performed on all EEGs collected at 12 months; this larger sample included 67 HR infants (27 HR-ASD, 40 HR-noASD).ResultsUsing a combination of Pearson correlation feature selection and support vector machine classifier, 100% predictive diagnostic accuracy was observed at both 6 and 12 months. Predictive features differed between the models trained on 6- versus 12-month data. At 6 months, predictive features were biased to measures from central electrodes, power measures, and frequencies in the alpha range. At 12 months, predictive features were more distributed between power and nonlinear measures, and biased toward frequencies in the beta range. However, diagnosis prediction accuracy substantially decreased in the larger, more behaviorally heterogeneous 12-month sample.ConclusionsThese results demonstrate that speech processing EEG measures can facilitate earlier identification of ASD but emphasize the need for age-specific predictive models with large sample sizes to develop clinically relevant classification algorithms.

This paper presents a high-power heterojunction bipolar transistor (HBT) power amplifier (PA) module designed for GSM/EDGE applications. The proposed HBT PA employs a differential output stage that delivers high output power at a low supply voltage. A transformer-based output matching network is employed to combine the differential output signals. Through the selection of an appropriate capacitor value at the transformer's center tap, linearity is enhanced across a wide bandwidth without requiring additional second harmonic termination. When assembled with a low-pass filter and an antenna switch, the PA module achieves an output power of 36 dBm and a power-added efficiency (PAE) exceeding 40% in GSM mode. In EDGE mode, it delivers an output power of 28.5 dBm with a PAE exceeding 20%. Additionally, the designed PA module achieves an adjacent channel power ratio of -60 dBc at a 400 kHz offset with an output power of 28.5 dBm.

The trends in RF power amplifier (RFPA) modules for handsets are optimization of active device technology, circuit topology and packaging to enhance cost, size, performance, and ease of implementation. For the package in RFPA module manufacturing, device-to-board attach solder reflow condition and moisture sensitivity level (MSL) are the most challenging areas for further improvement in thermal management due to "lead-free" application which causes catastrophic failure by high temperature application. In consequence, we have been faced with industrial requirements to improve both MSL and reflow temperature without any catastrophic phenomena such as solder extrusion and solder flow in RFPA modules. This paper discusses various considerations to define critical factors that will affect thermal and moisture induced stress in RFPA modules in long term reliability assurance at the package design stage. On the analysis of severe failure mechanisms in RFPA modules, we identified the cross effects on various characteristics of moisture induced package failures caused by the alloy composition of component terminations, behaviors of component attachment materials for active/passive, and substrate metallization with its own material. Also, best raw material combinations and critical consideration factors for package integrity of RFPA module with MSL reliability are discussed.

In this paper, a 3.2–3.6 GHz two-stage Doherty power amplifier (PA) module is proposed for fifth-generation (5G) massive multiple-input multiple-output (MIMO) base stations. A detailed design method and procedure for a compact and low-loss combiner suitable for the Doherty PA module are introduced. Based on the proposed combiner, a Doherty PA module is implemented using gallium nitride (GaN) transistors and surface-mounted devices (SMDs) with a packaged size of 8 × 8 mm2. The proposed two-stage Doherty PA module achieves a 3 dB small-signal bandwidth of 3.1–3.9 GHz and a peak gain of 31.7 dB. From 3.2 to 3.6 GHz, the saturated output power is 40.4–41.1 dBm. Moreover, the measured saturated drain efficiency (DE) and 8 dB power back-off (PBO) DE reach 51–56.6% and 45.5–48.6%, respectively.