Design consideration for modeless integrated circuit substratesusing planar periodic patches

In recent years, there has been significant interest in complete surface-wave elimination (meaning in all possible directions) through the use of periodic elements incorporated into integrated circuit structures. However, to date there is no comprehensive theory for the design of the surface-wave bandgap, and it also appears that leaky modes with complex propagation constants that may exist on the planar periodic structures have not been properly taken into account. As shown here, fast periodic leaky modes may exist within a surface-wave bandgap zone. These leaky modes may result in more energy loss and crosstalk than the surface-wave modes and should be taken into account in circuit design. This paper presents theory and experimental validation for guided surface-wave and leaky modes on a printed circuit structure consisting of planar periodic metal patches over a grounded substrate. The existence of surface-wave bandgaps and leaky modes is attributed to either element resonances or the weakly bounded dielectric slab modes. It is also found that fast periodic leaky modes may exist within a surface-wave bandgap zone. Design procedures for achieving a complete surface-wave bandgap without leaky-modes are outlined and examples are given     

3G系统RB快速重配功能减小业务建立时延优化

本文通过对3G业务建立过程中时延的分析,找出在RB配置时流程中可以优化的地方,减少业务建立时延300 500 ms,提升业务建立速度20%左右,有效改善了用户对于业务的使用感受。     

A reduced surface-wave twin arc-slot antenna for millimeter-waveapplications

A simple, uniplanar, reduced surface-wave twin arc-slot antenna element for millimeter-wave (mm-wave) integrated circuit antenna systems is presented. This design allows for almost complete surface-wave cancellation and resonance to be achieved simultaneously. Measured far-field radiation patterns on an electrically thick substrate are in very good agreement with theory and show little evidence of surface-wave propagation     

Characteristics of space and surface waves in a multilayeredstructure [microstrip antennas]

Characteristics of space- and surface-wave fields produced by an electromagnetic source in a multilayered structure are explored. Using the integral transformation technique it is shown that the space and surface-wave modes are orthogonal along the longitudinal direction with respect to an appropriate weighting function. It is demonstrated that these properties, together with reciprocity, can be utilized to determine the amplitudes of various surface-wave modes produced by an arbitrarily shaped source. Numerical results for the space- and surface-wave power for a circular patch antenna are presented. The study may find application for millimeter-wave printed antennas where the surface waves will play an important role in determining the radiation and impedance characteristics     

Surface waves on a grounded dielectric slab covered by a periodically slotted conducting plane

The surface-wave modes in a dielectric slab covered by a periodically slotted conducting plane are investigated. Two methods-sampling and variational-are used to obtain the surface-wave modes. The dispersion curves obtained by the two methods agree very well. The experimental and the theoretical results are in good agreement, except close to the stopband.     

New cut of quartz for SAW devices with extremely small temperature coefficient

A new cut of quartz for SAW devices was discovered by a leaky surface-wave mode. The temperature stability is extremely high and experimental temperature dependence of the phase delay change is within ±10 parts in 106 for the range from ?20 to 80°C. The propagation loss is only 2.6×10?4 dB/?.     

Acoustic surface waves on paratellurite

Numerical calculations of surface-wave properties and their temperature dependence have been carried out for the principal planes of paratellurite. The surface-wave velocity is shown to have large anisotropy, and several directions with zero temperature coefficients of delay are found.     

Surface-wave parametric signal processing

The parametric interaction of surface-wave signals propagating in opposite directions on a lithium-niobate substrate has been used to obtain the crosscorrelation of digitally coded input signals. The output 4 cm interdigital transducer was separated from the substrate by a 2000 ? SiO2 layer to eliminate scattering into volume waves. Matched-filter responses for both amplitude-modulated and biphase Barker codes of up to 13 bits have been obtained.     

Design of Modulated End-Fire Antennas

The design presented in this article is dedicated to end-fire antennas with a modulated surface-wave structure fed by a dipole or crossed dipole. For short, these are herein called modulated end-fire antennas. The studies were carried out with a modulated corrugated-rod (disks attached to a metal rod) surface-wave structure. The results obtained may be applied to other types of surface-wave structures, such as dielectric on a metal rod or dipole. The length of the investigated antennas ranged between 1.5lambda and 4.5lambda . The increase in directivity obtained was between 5 dB and 3.5 dB, compared to ordinary non-modulated end-fire antennas with the same lengths.     

Tunable high-Q surface-wave comb filter

Comb filters with tunable passband characteristics have been achieved using a muItitap surface-wave delay line with electronic phase-shifting circuits in the feedback loop. The results are obtained either by summing the acoustic signals on the substrate or by using electronic summers. Q's ranging from 500 to 50 000 have been measured for the surface-wave comb filters.     

Active surface-wave directional coupler

We report experimental results which show that noncollinear surface-wave mixing on [111]-cut bismuth?germanium oxide can be used to realise an active, switchable directional coupler. For low-level inputs, the coupling is enhanced by as much as 20 dB by a semiconductor placed over the interaction region. The directivity is found to be greater than 40 dB.     

Mutual coupling between reduced surface-wave microstrip antennas

An investigation of the mutual coupling between reduced surface-wave microstrip antennas is presented and compared with that for conventional microstrip antennas. Numerical results are presented from a theoretical analysis of the mutual coupling along with confirming experimental results. It is shown that for electrically thin substrates, the space-wave coupling, not the surface-wave coupling, is predominant for typical element spacing, for both the conventional and reduced surface-wave antennas. In addition, the mutual coupling behavior is examined using an asymptotic analysis, which demonstrates how the coupling falls off much faster with patch separation for reduced surface wave antennas compared to conventional microstrip patch antennas     

Multiple UHF frequency generation using acoustic surface-wave filters

A new technique of using acoustic surface-wave filters for multiple UHF frequency generation has been demonstated. The 21 contiguous surface-wave filters, which are spaced 5.3 MHz apart from 520 to 650 MHz, occupy an area of 2 cm × 0.9 cm, and no multipliers or mixers are required.     

邑磁带隙材料设计口径耦合微带天线

将电磁带隙材料用于孔径耦合微带天线的设计，利用其频率带隙抑制天线中激励的表面波，分别考虑高介电常数和低介电常数的情况。仿真和实验结果均证明在表面波的影响比较显著的情况下，电磁带隙材料的引入可以有效的抑制表面波的传播，从而改善原有天线的性能。从设计的例子来看，对于孔径耦合微带天线，在提高增益上的作用更显著。     

Electrically controlled acoustic-surface-wave filters

The field-effect transistor is used for a linear control of the acoustic radiation of single-electrode section of the surface-wave transducer. The electrically controlled surface-wave filters and delay lines, the characteristics of which may be specified by a set of constant control voltages, are described on this basis.     

Efficiency and gain of slot antennas and arrays on thick dielectric substrates for millimeter-wave applications: a unified approach

A unified approach for representing the surface-wave fields and for computing the corresponding radiation efficiencies from arbitrarily shaped slot-type antennas on thick dielectric substrates at millimeter-wave (mm-wave) frequencies is presented. In this approach, two different representations of the surface-wave fields, i.e., the one based on the idea that the surface-wave power can be associated with a substrate radiation pattern and the other based on the cylindrical wave expansion, are linked together in a unified way. The developed theory is then applied for investigating the surface wave characteristics of printed twin offset slots and uniform linear slot arrays. Based on the developed theory, new insight into the mechanism with which surface-wave power is coupled by the slot pair is presented. Subsequently, the optimum number of elements and corresponding interelement spacing for linear, uniformly excited, slot dipole arrays is explored for achieving maximum radiation efficiency and gain. In order to provide guidance on practical mm-wave integrated slot antenna array design, supportive numerical results are presented for Substrates of dielectric constant /spl epsi//sub r/ = 4.0 and /spl epsi//sub r/ = 12.0.     

Aperture-coupled patch antenna on UC-PBG substrate

The recently developed uniplanar compact photonic bandgap (UC-PBG) substrate is successfully used to reduce surface-wave losses for an aperture-coupled fed patch antenna on a thick high dielectric-constant substrate. The surface-wave dispersion diagram of the UC-PBG substrate has been numerically computed for two different substrate thickness (25 and 50 mil) and found to have a complete stopband in the frequency range of 10.9-13.5 and 11.4-12.8 GHz, respectively. The thicker substrate is then used to enhance broadside gain of a patch antenna working in the stopband at 12 GHz. Computed results and measured data show that, due to effective surface-wave suppression, the antenna mounted on the UC-PBG substrate has over 3-dB higher gain in the broadside direction than the same antenna etched on a grounded dielectric slab with same thickness and dielectric constant. Cross-polarization level remains 13 dB down the co-polar component level for both E- and H-planes     

A technique for approximating the location of surface- and leaky-wave poles for a lossy dielectric slab

An approximation technique for locating the surface- and leaky-wave poles for a lossy dielectric slab is presented. The problem is reduced to the simultaneous solution of two transcendental equations (for each of the perfect magnetic conductor (PMC) and perfect electric conductor (PEC) cases) which is shown to yield a simple approximate solution for the poles, and which can subsequently be refined using numerical optimization. The technique yields both surface-wave and leaky-wave poles, and results are presented for a typical example to demonstrate the approach. The greatest approximation accuracy was observed for surface-wave and leaky-wave poles well removed from the spectral gap. For poles either within or in close proximity to the spectral gap, an alternative iterative technique is proposed. Expressions for the number of proper plus improper surface-wave poles in a given problem are also derived.     

Surface-wave radiation loss from curved dielectric slabs and fibers

A newly developed systematic procedure to calculate the real and imaginary parts of the change in propagation constant of a surface-wave mode on a curved open waveguide of general cross section is used here to determine these quantifies for the TE modes of an asymmetric slab waveguide and for all the modes of an optical fiber. Comparison of these results with the existing literature points up the care which must be taken in making approximations in this problem, since errors of significant factors in the radiation loss have been made in previous work.