LTCC-MLC chip-type balun realised by LC resonance method

A multilayer ceramic balun designed in the 2.4 GHz ISM band frequency is presented. A multilayer structure to realise the low temperature co-fired ceramic (LTCC) balun is proposed. This type of balun comprises an embedded capacitor and meandered or spiral coupled lines. The use of an LC resonator can shrink the length of a coupled transmission line and can be designed very easily to have various balanced output port impedances. Excellent performance of phase and amplitude balance may be achieved by the proposed method. Measured results of the LTCC-multilayer ceramic (MLC) balun match well with the computer simulation     

New uniplanar balun

A new uniplanar CPW-slot double junction balun has been proposed. Being realised as a uniplanar equivalent of the microstrip-slot double junction transition, this balun is well suited for MMICs, and has better characteristics that other uniplanar baluns published up to now. The measured VSWR is less than 1.6 and insertion loss is about 0.7 dB for bandwidth ratio 1:6.<>     

New broadband balun

The letter describes a new balun composed of a modified `rat race? with an open-circuit impedance at the uncoupled port. The advantage of this device is the great bandwidth, together with its very small dimensions. The performance of a layout on an alumina substrate is compared with theorotical predictions. For a midband frequency of 2.5 GHz, a bandwidth ratio of 52% and dimensions smaller than 1 cm2 on a 10 mil-thick alumina substrate are typical.     

埋容电路用高介电常数热塑性聚酰亚胺的性能研究

通过填料预分散法和原位聚合法合成了一种BaTiO3填充的热塑性聚酰亚胺树脂。考察不同填充量的填料对热塑性聚酰亚胺的力学性能,热性能和电性能的影响。结果发现:随着BaTiO3添加量的增大,TPI的介电常数和介电损耗都增大,力学性能急剧下降,尤其是柔韧性急剧降低;玻璃化转变温度不变,热分解温度相应增加,热膨胀系数减小,吸潮率降低,TPI与铜箔之间的粘接力减少。     

Chip-type LTCC-MLC baluns using the stepped impedance method

A chip-type low-temperature co-fired ceramic (LTCC) multilayer ceramic (MLC) balun is presented in this paper. This balun is designed using the stepped impedance method. It uses a multilayer structure, meander lines, and multisection coupled lines. The use of multisection couple lines that have various characteristic impedance ratios can shrink the length of a quarter-wavelength coupled-transmission line and makes it very easy to match various impedances of balanced output. The proposed chip-type balun operates over a bandwidth of 2.25-2.65 GHz. The in-band phase and amplitude balances are excellent because of the symmetric structure and transmission-line trimming section. Measured results of the chip-type LTCC-MLC balun match well with the computer simulation     

Four decade bandwidth uniplanar balun

A new realisation of a double junction balun with four decade bandwidth is presented. The balun is designed using coplanar line (CPS) and coplanar waveguide with finite ground planes (CPW/sub FGP/). The simple theoretical model which describes the double junction balun as the all-pass network has been introduced. The measured VSWR is less than 1.3 and insertion loss less than 0.5 dB in the frequency range 300 kHz-4.0 GHz.<>     

Compact and broad-band three-dimensional MMIC balun

This paper presents a simple and effective technique which compensates for the amplitude and phase differences of the Marchand balun. Compensation is accomplished by interconnecting a short transmission line to a pair of couplers. As a result, Marchand balun with operation frequency ranging as wide as 8.2-30 GHz is achieved. To fabricate the prototype, we adopt three-dimensional monolithic-microwave integrated-circuit technology together with a 2.5 μm×4 layer polyimide structure stacked over a GaAs wafer. The topology yields a circuit area as small as 0.2 mm×0.4 mm for the balun     

无线收发前端小型化巴伦的研究

针对射频前端的小型化巴伦展开研究,在理论分析上,从变压器型巴伦的原理出发,将电磁场数值方法和微波网络理论相结合,将标准散射（S）参数和混合散射（S）参数相结合,提出了新颖的巴伦特性的理论研究方法;在实际应用上,利用高阻性硅基集成无源器件（Integrated Passive Device,IPD）技术,经过电磁仿真和优化,设计和制作了基于交叉耦合平面螺旋线结构的小型化变压器型巴伦.巴伦的尺寸仅为1.85 mm×1.6 mm,10 dB单端回波损耗带宽为2.07~2.80 GHz,频带内插入损耗小于0.98 dB,差分对幅度失配小于0.43 dB,相位失配小于3.8°,仿真结果得到了实验验证.     

板线平衡器在八木天线中的应用

文中提出了用于八木天线的新型馈电结构———板线平衡器。给出了详细的板线平衡器和八木天线的设计过程及仿真和试验结果。在仿真设计的基础上制作了试验模型,并对其进行了测量。实验结果表明：板线平衡器具有设计灵活、耐高功率等特点。该天线既可当常规天线使用又可作为高功率宽频带阵列天线单元。     

Integrated low-loss balun for Vivaldi antennas

A low-loss balun is presented that can be integrated on the low-permittivity substrates usually used in the construction of the adjoining Vivaldi antenna for improving the antenna radiation. However, it also increases the unwanted radiation of the feeding balun required for impedance matching and mode conversion. The radiation losses of the balun are reduced by limiting the size of balun, which is achieved by cladding the balun with slabs of high permittivity dielectric.     

Passive broadband millimetre-wave uniplanar MMIC balun

A new uniplanar monolithic microwave integrated circuit (MMIC) balun using lumped circuits is presented. The proposed planar balun consists of a wideband Wilkinson power divider and a broadband 180° phase shifter using novel series and parallel LC reflective terminating circuits. To demonstrate the design methodology, a 24?44 GHz MMIC balun was realised as a 1.4 mm _{GaAs chip. The measured return losses for the unbalanced and balanced ports are better than 212, 210 and 27 dB, respectively. The measured amplitude and phase imbalance between the two output ports are less than 0.5 dB and 7°, respectively, and maximum insertion loss is 5 dB.}     

A novel LTCC miniaturized dualband balun

In this letter, a novel low temperature cofired ceramic (LTCC) miniaturized dualband balun using a tapered line structure has been presented. The key concept for our dualband solution is by employing tapered line structures in the conventional Marchand baluns. In our new design, we have demonstrated the tapered line structure can shift the periodic operation frequency to a desired frequency band. A sample balun design has been presented. The novel LTCC dualband balun has been simulated and verified by measurement. The measured results exhibit that the proposed balun can easily cover the important radio frequency bands at 2.4GHz, 5.25GHz, and 5.85GHz.     

Miniaturised branch-line balun with bandwidth enhancement

A miniaturised branch-line balun with bandwidth enhancement is investigated. The improved performance is achieved by meandering the branches and attaching a quarter-wavelength stub at the upper right corner of the conventional branch-line balun. Centred at 1.5 GHz, the introduced balun is optimally designed and validated by experiments. A circuit size of 20% is achieved as compared to the conventional type, and good electrical performance is observed.     

小型LTCC巴伦的设计

提出了一种基于Marchand巴伦结构的小型化半集总参数巴伦.通过加载端电容和谐振电容减小巴伦耦合线电长度,LTCC多层布线的实现方式进一步减小了巴伦的实际体积.采用奇偶模分析方法对该结构进行分析,给出了设计曲线,采用A6——M材料仿真并制作出尺寸为2.5 mm×2.0 mm×1.0 mm的巴伦.测得在2.7～2.9 ...     

Half-VCC sheath-plate capacitor DRAM cell withself-aligned buried plate wiring

A trench-capacitor DRAM cell called a half-V_CC sheath-plate capacitor (HSPC) cell has been developed using 0.6-μm-process technology. It is applicable to DRAMs with capacities of 16 Mb and over. The HSPC cell achieves a storage capacitance of 51 fF in a cell area of 4.2 μm² and excellent immunity (critical charge Q_c<35 fC) against alpha-particle injection. These advantages are achieved using a half-V_CC sheath-plate structure, a 5.5-nm SiO₂-equivalent Si ₃N₄-SiO₂ composite film, and three self-alignment technologies involving buried plate wiring, a sidewall contact and a pad for the bit-line contact. The device performance is evaluated using an experimental 2-kb array     

Optimim design for a broadband microstrip balun

The letter reports calculations of Marchand balun performance which show that bandwidths approaching 50:1 (for a V.S.W.I.?2:1) should be achievable with overlaid microstrip structures. The bandwidth limits (?8:1) reported by previous writers appear to reflect only the inaccessibility of the true optimum to the semiempirical design methods used and the limitations of fabrication on single-thickness card. Preliminary experimental results confirm the theoretical indications.     

Modeling of monolithic RF spiral transmission-line balun

This paper presents models for monolithic RF spiral transmission-line baluns. The balun consists of a pair of spiral transformers fabricated on high-resistivity silicon. The lumped-element equivalent models are developed. The second-order or higher order models are synthesized from the first-order lumped model. All lumped parameters for the models are extracted from the real physical structures. Simulated behaviors from the second-order models are in good agreement with the measured results within 10% difference     

On-chip micromachined solenoid balun for RF-SOC applications

A transformer balun is fabricated by using a post-CMOS compatible MEMS process. The novel concave-suspended solenoid balun can be integrated with radio-frequency system-on-chips (RF-SOCs). In the frequency range 0.5-10 GHz, the tested balun shows less than 0.7 dB amplitude imbalance and less than 1.5deg phase imbalance. After tuning, the transformer balun can match between a 100 Omega single-ended port and two 50 Omega differential ports. At the two differential ports, insertion losses of -1.5 and -0.8 dB are obtained at 5-GHz centre frequency, more than 40% bandwidth of S ₁₁ is achieved.