Just do copy past it will work. Even if not work just keep gap top of the summary band and first element to make sure it consider break.
set below jasper property in top of the report.
<property name="net.sf.jasperreports.export.xls.sheet.names.all" value="First
sheet/Second sheet/Third sheet" />
Add break to see that part in separate worksheet.
<summary>
<band height="110">
<printWhenExpression><![CDATA[$V{MAIN_REPORT_TABLE1_COUNT}>=1]]></printWhenExpression>
<textField>
<reportElement X="0" y="0" width="1000" height="40" >
<property name="net.sf.jasperreports.export.xls.break.before.row" value="true"/>
</reportElement>
<textElement> <font size="24" isBold="true"/></textElement>
<textFieldExpression><![CDATA["Search Criteria"]]></textFieldExpression>
</textField>
</band>
</summary>
