<!--
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```js
option = {
angleAxis: {
},
radiusAxis: {
type: 'category',
data: ['周一', '周二', '周三', '周四']
},
polar: {
},
series: [{
type: 'bar',
data: [2, 3, 3, 4],
coordinateSystem: 'polar',
barMaxWidth:20,
itemStyle: {
normal: {
barBorderRadius: 10
}
}
}]
};
```

### 笛卡尔坐标系正常
```js
option = {
yAxis: {
},
xAxis: {
type: 'category',
data: ['周一', '周二', '周三', '周四']
},
series: [{
type: 'bar',
data: [2, 3, 3, 4],
barMaxWidth:20,
itemStyle: {
normal: {
barBorderRadius: 10
}
}
}]
};
```

### Other comments [其他信息]
<!-- For example: Screenshot or Online demo -->
<!-- [例如,截图或线上实例 (JSFiddle/JSBin/Codepen)] -->
[ Full content available at:
https://github.com/apache/incubator-echarts/issues/9085 ]
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