Quasi-optical 150-GHz power combining oscillator

A quasi-optical power combiner for a five-element in-line oscillator array is experimentally investigated at 150 GHz. The combiner consists of a periodic dielectric phase grating (hologram) which transforms the near-field of a rectangular horn antenna array into a pseudo-plane wave. The horn array is excited by IMPATT oscillators operating uniformly in both amplitude and phase. A dual offset reflector set-up transforms the pseudo-plane wave to a Gaussian beam which matches the field pattern of a dual mode receiving antenna. Even though an inter-element spacing of 9.5 /spl lambda/ has been chosen, the passive structure gives a power combining efficiency of 74.1%. The power combining oscillator has been operated in both free-running and injection-locked mode. A CW output power of 78.0 mW and 83.5 mW was measured for the free-running and injection-locked oscillator, respectively, which is corresponding to a power combining efficiency of 66.5% and 71.2%, respectively.     

Spatial power divider/combiner in D-band

Five-element spatial power divider/combiners have been realized at 150 GHz. Holography is applied to couple the field pattern of an in-line rectangular horn antenna array to a pseudoplane wave. The hologram is realized as periodic phase grating. The transformation of the pseudoplane wave to a Gaussian beam is performed by phase modulation with a dual-offset reflector on the one hand, and a system of Fresnel lenses on the other hand. Both setups have been extensively examined. The analysis has been enhanced by a vector near-field measurement system. The comparison of the simulated and measured efficiencies, as well as field distributions shows good agreement.     

一种8 mm频段封闭腔全息准光功率合成网络的设计

基于周期相位栅格的塔尔博特效应,提出了一种新型的毫米波频段18合1封闭腔全息准光高效功率合成网络。采用了相邻半周期相差仔的特殊周期相位栅格,置于垂直于栅格的零场区域的金属壁封闭了合成网络,解决了辐射损耗和电磁泄漏问题。基于光学标量衍射理论算法仿真的衍射图样与目标场对比得到的适应度函数,以基因算法优化得到相位栅格,并以变宽波导阵透镜物理实现。在37.5 GHz,功率合成网络实物测试的效率为81%,与电磁仿真的89%基本相符。准光功率合成网络可由一维扩展至二维,合成效率与阵元数、阵元间距无关,可实现毫米波及THz频段的大规模数量器件高效功率合成。     

Broadband Analysis of Holographic Power Combining Circuits

Holography is a promising technique for power combining applications in the frequency range of short millimeter and submillimeter waves. In this paper, quasi-optical holographic power combining circuits are investigated. An equivalent network is utilized which rigorously models horn arrays and biperiodic dielectric structures in order to design computer-generated holograms. We apply the network model to a 5-element quasi-optical power combiner and demonstrate its capability. The hologram is designed for 150 GHz and has an efficiency of 92.5 % with a 90 % bandwidth of 5.3 %. With the aid of a broadband waveguide power divider and a vector field measurement system, the circuit is analyzed.     

Diffraction synthesis and experimental verification of a quasi-optical power splitter at 150 GHz

A general and flexible synthesis method based on the physical optics approximation is proposed for computing smooth-surface reliefs of reflectors. As a design example, the method has been applied to a quasi-optical power splitter consisting of two reflectors in a dual-offset configuration that couples a launched beam from a pyramidal horn antenna into a 2/spl times/4 horn antenna array. The two reflectors were treated as diffractive phase elements so that the proposed synthesis method allows reflector designs for many applications. The quasi-optical design has been confirmed at 150 GHz utilizing a vector field measurement system. The measured field distribution in the receiving antenna array plane is compared with the simulated one and shows a very good agreement.     

Millimeter-Wave Power Combiner Using Quasi-Optical Techniques

A millimeter- or submillimeter-wave combiner using a quasi-optical open resonator to effectively combine the power output of several solid-state oscillators to a single-frequency is described. The combiner makes use of a symmetrical concave spherical resonator with dielectric wedge launchers as energy couplers. To demonstrate feasibility of this concept, experiments were carried out by using two InP Gunn oscillators at 60 GHz, and a combining efficiency of 54 percent has been achieved.     

Global optimization method in millimeter wave combiner

This paper describes an algorithm which can determine the global optima of the power combiner of solid-state millimeter wave resonator. The global optimization mehtod can determine a neighborhood of the global optima of an objective function and an estimation of the global optima. In this paper the objective function as follow: In the quasi-optical resonator, the objective function are the fundamental mode power, the fractional power of fundamental mode and the combining dfficiecy were done the objective functiona respectively, to calculate the global optima respectively. In the power combiner of solid-state millimeter wave source in rectangular waveguide cavity. the performance parameter are presentes by combining efficiency, tuning range, frequency drift, and FM noise were done the objective functions respectively. And to calculate the global optima respectively.     

28 GHz omni-directional quasi-optical transmitter array

Omni-directional base stations are needed in many emerging wireless communication systems. This paper presents the first adaptation of a quasi-optical oscillator array for this purpose. A 28 GHz active oscillator element containing a modified Vivaldi endfire antenna is utilized as the unit cell. Twelve of these are incorporated into the circular array, which is powered from a single DC power supply. The array has a high combining efficiency and remains frequency-locked over a span of 600 MHz     

稳定型准光腔外衍射场计算

稳定型准光腔外衍射场的计算是实现准光功率合成与天线一体化设想的关键性问题。本文在A.L.Cullcn提出的准光腔复源点理论和L.B.Felsen提出的复射线理论基础上结合几何分析和计算,得到了E和H平面远区方向性图。本文的计算与实验结果基本吻合。     

A demonstration of the coupled oscillator based agile beam receiver concept

The Cao-York concept of using a linear array of mutually injection locked oscillators to provide local oscillator signals for an agile beam receiver is demonstrated using a 15 circuit array of L-band voltage controlled oscillators coupled to nearest neighbors. The concept involves mixing each 1.265 GHz local oscillator (l-o) signal with a corresponding 1.950 GHz signal received by an element in an antenna aperture and combining the resulting 685 MHz intermediate frequency (i-f) signals. A normally incident wave is simulated using a power divider to provide 15 equal in-phase signals to the r-f ports of the mixers and the i-f combining is accomplished using a similar power divider in reverse. The "antenna beam" is steered through this "normally incident wave" by antisymmetrically detuning the end oscillators of the array and a plot of the i-f combiner output represents the receive beam shape. Finally, this system is used to demonstrate the Kott sidelobe suppression technique.     

3-mirror quasi-optical power combining of millimetre-wave sources

In order to achieve high power readily for applications such as plasma heating in fusion, it is required that the outputs of several gyrotron tubes be combined. A new kind of 3-mirror quasi-optical power combiner has been presented and studied in this paper. Both theoretical and experimental study point out that the proposed power combiner has attractive features. It seems that this 3-mirror quasi-optical power combiner may not be used only for high power millimetre gyrotron power combining, but also for millimetre and submillimetre solid state power combining     

Combination dielectric resonator, power combiner, and antenna

A rectangular dielectric resonator housed in a cutoff parallel-plate waveguide is used both as a radiating element and microwave power combiner. The resonator is excited by using tuned electrically short monopole antennas to induce a longitudinal electric operating mode. The resonator is then used in conjunction with free-running oscillators in order to provide, via mutual injection locking, stable in-phase power combining. Furthermore, the resonator is arranged such that one of its faces radiates a portion of the power-combined signal. Since the resonator is housed in a cutoff waveguide, the cross-polarization radiation from the antenna is suppressed. It was found that, for a single element, a gain in the azimuthal plane of 5 dB could be achieved and, for a two-element array, a gain of 7 dB was obtained with better than -25-dB cross polarization for each case. The oscillator power-combining efficiency for a single-element antenna (two oscillators) was 91%, and the spatial power-combining efficiency for a two-element antenna array, (four oscillators) was found to be 90%. In addition, it is shown that the presence of the dielectric inserts in conjunction with coupled oscillator dynamics provides moderate overall oscillator phase noise improvement     

宽带高效径向波导基空间功率合成技术

为获得振幅和相位一致性较好的空间功率合成结构,对径向波导电磁场分布进行了理论分析,推导出径向波导内存在TM_(00)主模.根据TM_(00)波电磁场的轴向对称性,提出了径向波导功分器的简化电磁模型和等效电路.并由此研制出了性能良好的X波段159 W固态功率放大器.在整个X波段,无源合成网络的合成效率都大于88%.含单片微波集成电路芯片(MMIC)的整体合成固态功放合成效率在整个MMIC工作频率范围内(11.9～12.3 GHz)大于83%.     

毫米波300W固态功率合成放大器的设计

基于单片微波集成功率放大器(Monolithic Microwave Integrated Circuits,MMIC PA)的毫米波波导空间功率合成技术是固态毫米波高功率电子领域的热门研究方向。多合成支路情况,保持较高的合成效率和较宽的工作带宽是实现固态毫米波宽带高功率合成的关键技术难题。为提高功率合成效率,研制了石英基板微带探针与波导之间的过渡结构。结合波导T型分支、波导分支线、波导H面缝隙耦合和波导一分四型的4种波导功率分配/合成器,通过精确的电磁仿真研制了64路功率合成放大器。     

Monolithically integrated Gunn oscillator at 35 GHz

A fully planar monolithically integrated Gunn oscillator for 35 GHz has been constructed on a GaAs substrate. An output power of about 1.5 mW, corresponding to an efficiency of 0.5%, is obtained from the oscillator in its present unoptimised form. The device is intended for use as a local oscillator in integrated millimetre-wave receivers. Measurements are made by means of quasi-optical output coupling.     

（英）亚毫米波波段波束功率合成方法

对于亚毫米波或太赫兹系统而言,关键问题是功率源的输出功率非常小。 功率合成技术是增加输出功率的有效方法。 然而,在微波和毫米波段中使用的常规功率合成方法（例如电路级合成或波导内空间合成）在亚毫米波波段因损耗高及难以加工等因素而受到制约。 本文提出了一种基于准光学技术的波束功率合成方法。 它具有损耗低,合成效率高,相对容易制造的优点。本文给出了分析,仿真和实验结果,并得到高的输出合成效率。     

A new kind of compound solid-state quasi-optical power combiner

In this paper, a new kind of solid-state quasi-optical power combiner is presented. It consists of two or more singlecavity multiple-device power combiners and a Fabry-Perot cavity. The experimenal results using six Gunn diodes at X-band show that the total output power is higher than 400 mW, the total combining efficiency is as high as 83%, and the frequency stability is better than 10^?5.     

An analysis of small aperture multimode horn as quasi-optical Gaussian beam radiator

In this paper a small aperture multimode horn is analysed by full-wave method and the coupling efficiency to Gaussian fundamental mode is calculated. The coupling efficiency of exceeding 0.98 is obtained over 4 GHz bandwidth. This horn may be used to connect waveguide with quasi-optical element in millimeter wave system and also may be used as an element in imaging array.