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It is noted that the capture range is related directly to the signalsymbol rate. Here we will consider the impact of the tuner's step size on the capture of the signal.Assuming that the tuner would not introduce any changes to frequency offset and drift while adjusting its operating frequency with the specified step size, the minimum signal-symbol rate to guarantee 100% capture of the signal is determined by the tuner frequency step size Ϯ62.5 KHz and symbol-rate-related capture range; the minimum signal-symbol rate needs to be the one corresponding to a Ϯ31.25-KHz capture range.By linealizing the relationship between capture range and signal-symbol rate, it is found that the minimum signal-symbol rate to guarantee 100% capture of the signal is 1.054 Ms/s. CONCLUSIONA Monte-Carlo simulation model has been developed to investigate the issues related to symbol rate, signal-capture probability, and temperature changes in the microwave LMDS systems. Numerical data have been presented. Symbol-rate limitations were presented to guarantee 100% probability of signal capture. The simulation approach and analysis may be applicable to other microwave/millimeter-wave radio-access systems and wireless LAN systems. EBG antennas (see [9,10]) are very thin, high-gain antennas. They can be modified and designed to exhibit directive patterns for multiple distinct frequencies and hence they become multifrequency dielectric EBG antennas.Multifrequency antennas are very useful today in the telecommunications domain because they provide system integration, combining multiple functions and decreasing the number of antennas required. PRINCIPLEThe principle is based on the EBG resonator antenna described in [9], where it was shown that a defect in the periodicity of the EBG material can open a transmission frequency band inside the frequency band gap of the regular lattice.The defect introduced into the EBG structure is obtained, for example, by an air gap in a regular 1D crystal. An electromagnetic probe on a ground plane (here, a patch antenna) excites the structure, then the radiation pattern of the antenna exhibits a narrow beam with very low side lobes at the transmission frequency.However, one interesting property is that a single defect (the air gap) opens several transmission bands, then the multiple operation modes allow the antenna to operate for different frequency bands. Operation ModesOne defect creates several transmission bands. But these must be in the band gap in order to obtain a working antenna. To create multiple transmission bands in the band gap, it is necessary to design an EBG material that exhibits a wide band gap. This is possible when the relative permittivity contrast between the two dielectrics is large. It is also necessary to set the transmission bands inside the band gap. To do this, the air gap must be well dimensioned: the electrical length of the defect must be a multiple of g / 2 for the desired functioning frequencies.For example, Figure 1 shows the transmission factor (solid line) of a 1D EBG struct...

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