A wideband compact parallel-strip 180/spl deg/ Wilkinson power divider for push-pull circuitries

A Wilkinson power divider with a differential output implemented in parallel-strip-line (PSL) is proposed. Taking full advantages of the PSL technology and a three-stage cascaded design, more than 170% impedance and isolation bandwidths are obtained. Inherent to the PSL structure, the 180/spl deg/ differential output is frequency-independent. A class-B push-pull power amplifier employing the devised concept is designed, showing a peak efficiency of 44% over a 4-GHz bandwidth. Without exploiting any extra and external low-pass filters, the proposed design can produce startling second-harmonic suppressions (more than 50dB) over the whole working dynamics and operated bandwidth.     

Waveguide to microstrip line transition and power divider

A novel waveguide to microstrip line transition and power divider with a planar structure is presented. The transition and power divider is designed on both sides of a single layer dielectric substrate, and can be used as a feed of an array antenna with a waveguide feed structure or as a complete integration of waveguide components with active components such as MMIC. Experimental results are shown and compared with simulations; it is shown that good return and insertion loss characteristics are obtained for the K-band     

Taper transmission line UWB Wilkinson power divider analysis and design

This paper proposed, analysed and fabricated an ultra-wideband Wilkinson power divider. This proposed power divider contains two parts, namely the transmission lines with fixed characteristic impedance and the tapered transmission line.

The power divider has a fixed architecture with the ability to broaden for different bandwidths by changing its circuit parameters including resistors and impedances. It also can create a bandwidth of about 40 GHz with a smaller physical dimension and fewer numbers of resistors.

The proposed power divider is investigated using the even/odd analysis method in order to compute equations required for designing power divider.

The proposed power divider was designed and fabricated for the 3-11 GHz ultra-wideband range. Then, the results are compared with the simulated results and a good agreement is obtained consequently. Furthermore, input return loss better than 12dB, output return loss better than 15dB, insertion loss better than 4.8dB and output ports isolation less than 12 dB are achieved by measured results. The overall size of the proposed power divider is 14.2 × 4.8 mm².     

一种微带结构的新型不等分功分器设计

为了满足天线阵波束赋形对各单元天线输入功率不等分配的要求,基于Wilkinson功率分配器设计理论,详细推导并给出了任意功分比情况下隔离电阻的计算公式,补充了目前参考资料中对于直接多路输出功分器的设计指导。通过引入二分之一波长微带传输线,提出了一种微带结构的新型不等分功率分配器的设计方法。基于此方法,实现了一款应用于海事卫星通信天线阵馈电网络的功分比为1∶2∶1的三路不等分功分器。仿真和实测结果表明,功分器在工作频带范围内具有良好的性能指标。     

基于左右手复合传输线的威尔金森功分器

基于左右手复合传输线(CRLH TL),提出了一种新型并行馈电的Wilkinson功率分配器.采用奇偶模分析方法证明了在Wilkinson功分器中用左右手复合传输线替代传统传输线的可行性,有效减小了功分器的尺寸.同时利用左右手复合传输线较平滑的相频特性,拓宽了新型左右手复合传输线功分器带宽.实测结果表明:和传统Wilkinson功分器相比,左右手复合传榆线功分器带宽能大幅度提高带宽,减小器件面积.另外与串行馈电CRLH功分器相比,由于左右手复合传输线Wilkinson功分器结构对称,各输出端口具有很好的相位一致性,隔离电阻的存在,使其各端口间也拥有较好的隔离度.     

Millimeter-wave waveguide-based out-of-phase power divider/combiner using microstrip antenna

A millimeter-wave waveguide-based out-of-phase power divider/combiner using microstrip patch antenna has been proposed in this paper. The stepped rectangular waveguide provides smooth impedance matching from standard rectangular waveguide to oversized rectangular waveguide. In order to obtain good amplitude balance, four symmetrical microstrip patch antennas are utilized. A Ka-band four-way passive power combiner is designed and measured. The measured results show a reasonable agreement with the simulated ones.     

Five-output optical power divider based on multichannel coupled waveguide structure

A novel five-output optical power divider with multichannel coupled waveguide structure has been developed. This device has been designed and simulated by the beam propagation method for evenly distributed power output and fabricated by the RF-sputtering technique on SiO/sub 2/ based material. Experimental observation of the output power distribution at a wavelength of 1.31 mu m indicated a port to port variation of less than 10% from the designed specification.<>     

180/spl deg/out-of-phase power divider based on double-sided parallel striplines

A novel 180deg out-of-phase power divider based on double-sided parallel striplines (DSPSL) is proposed. The proposed power divider has a relative bandwidth of about 100%. The 180deg out-of-phase characteristic between the two output ports is frequency independent, which is suitable for various applications of wide bandwidth. In addition, the characteristic impedance of the transmission lines for the input and output is 50 Omega, and it allows easy integration with other microwave components. The proposed power divider has been demonstrated and verified. The experimental results are presented and show good performance     

Highly linear 0.18-/spl mu/m CMOS power amplifier with deep n-Well structure

The linearity of a 0.18-/spl mu/m CMOS power amplifier (PA) is improved by adopting a deep n-well (DNW). To find the reason for the improvement, bias dependent nonlinear parameters of the test devices are extracted from a small-signal model and a Volterra series analysis for an optimized nMOS PA with a proper matching circuit is carried out. From the analysis, it is revealed that the DNW of the nMOS lowers the harmonic distortion generated from the intrinsic gate-source capacitance (C/sub gs/), which is the dominant nonlinear source, and partially from drain junction capacitance (C/sub jd/). Single-ended and differential PAs for 2.45-GHz WLAN are designed and fabricated using a 0.18-/spl mu/m standard CMOS process. The single-ended PA with the DNW improves IMD3 and IMD5 about 5 dB with identical power performances, i.e., 20 dBm of P/sub out/, 18.7 dB of power gain and 31% of power-added efficiency (PAE) at P/sub 1dB/. The IMD3 and IMD5 are below -40 dBc and -47dBc, respectively. The differential PA with the DNW also shows about 7 dB improvements of IMD3 and IMD5 with 20.2 dBm of P/sub out/, 18.9 dB of power gain and 35% of PAE at P/sub 1dB/. The IMD3 and IMD5 are below -45 dB and -57 dBc, respectively. These performances of the linear PAs are state-of-the-art results.     

Highly efficient xDSL line drivers in 0.35-/spl mu/m CMOS using a self-oscillating power amplifier

The design of two highly efficient line drivers in a digital 0.35-/spl mu/m, 3.3-V technology are presented. The self-oscillating power amplifier (SOPA) architecture has been developed in order to obtain a high efficiency for systems with a high crest factor like discrete multitone modulated xDSL modems. The SOPA architecture is an unclocked switching-type line driver. By using self-oscillation and noise-shaping, a high signal linearity can be obtained for low over-switching ratios. By coupling two SOPA line drivers with a signal transformer, the two limit cycle oscillations are pulled toward synchronization. This gives an important mean switching frequency suppression toward the line. The need for an extra filter dealing with the mean switching frequency is in that way heavily relaxed. A zeroth-order SOPA and a third-order SOPA are prototyped. The zeroth-order line driver meets ADSL-Lite specifications with a missing tone power ratio (MTPR) of 41 dB for an 800-kHz bandwidth. The maximum efficiency is 41%. The third-order version meets ADSL and VDSL specifications with an MTPR of 56 dB and an 8.6-MHz bandwidth. An efficiency of 47% was measured for an ADSL signal with a crest factor >5.     

Broadband 180/spl deg/ bit phase shifter using a /spl lambda//2 coupled line and parallel /spl lambda//8 stubs

In this paper, a broadband 180/spl deg/ bit phase shifter using a new switched-network was presented. The new network is composed of a /spl lambda//2 coupled line and parallel /spl lambda//8 open and short stubs, which are shunted at the edge points of a coupled line, respectively. According to a desired phase shift, it provides a controllable phase dispersive characteristic by the proper determination of Z/sub m/,Z/sub s/, and R values. The 180/spl deg/ bit phase shifter operated at 3 GHz was fabricated and experimented using design graphs which provide the required Z/sub m/,Z/sub s/ values, and I/O match and phase bandwidths. The experimental performances showed broadband characteristics.     

A new method to suppress harmonics using /spl lambda//4 bias line combined by defected ground structure in power amplifiers

A new /spl lambda//4 bias line combined by a dumb-bell shaped defected ground structure (DGS) is proposed to suppress harmonics in power amplifiers. The proposed DGS bias line maintains the required high impedance even after DGS is inserted, while the width and length of the /spl lambda//4 bias line are broader and shorter than those of conventional bias lines. When the DGS bias line is used in power amplifiers, the third harmonic components as well as the second harmonic are reduced, because of the increased slow-wave effect over wide harmonic band. It is shown that the reduction of the third harmonic component, the improvement of 1 dB compression point, and power added efficiency are 26.5 dB, 0.45 dB, and 9.1%, respectively.     

Ultra-wideband (UWB) power divider with filtering response using shorted-end coupled lines and open/short-circuit slotlines

A novel ultra-wideband (UWB) power divider with bandpass-filtering frequency response has been presented. The shorted-end coupled lines and the open/short-circuit slotlines are introduced to this presented power divider. An isolation resistor R is located across the slotline for improving the isolation between the output ports of the power divider. Based on even and odd mode analysis, an analytical model of the presented power divider structure has also been proposed. An UWB power divider with passband response has been designed, fabricated, and measured. The measured results verify the predicted attractive features. It can be seen that the presented UWB power divider can not only divide/combine the power of microwave signals, but also reject unwanted frequency signals to better regulate the UWB performance.     

Highly efficient 40-GHz bandwidth Ti:LiNbO3 opticalmodulator employing ridge structure

The design and fabrication of a Ti:LiNbO₃ optical modulator employing a ridge structure with a shielding plane are described. The ridge structure offers a relatively low microwave propagation loss and large interaction between the microwave and optical wave under the condition of a 50 Ω characteristic impedance system, resulting in a large modulation bandwidth and low driving voltage. As a result, a 3-dB optical bandwidth of 40 GHz with a driving voltage of 3.6 V is achieved at 1.5 μm     

Low power 10 GHz ring VCO using source capacitively coupled current amplifier in 0.12 /spl mu/m CMOS technology

A 10 GHz ring voltage controlled oscillator (VCO) has been designed and implemented in 0.12 /spl mu/m CMOS technology. A source capacitively coupled current amplifier (SC3A) is adopted to realise this VCO. It can operate from 8.4 GHz up to 10.6 GHz with a phase noise of about -85 dBc/Hz at 1 MHz frequency offset. With the 1.5 V supply voltage, the current consumption is about 35 mA.