This paper studies flexible non-uniform array design for monostatic integrated sensing and communication (ISAC) systems. An antenna pool is considered at the base station, where each candidate antenna can be dynamically assigned to transmit, receive, or inactive modes, such that a non-uniform effective array is jointly constructed with the ISAC precoding design. We formulate a sum communication rate maximization problem by jointly optimizing the ISAC beamforming schemes and antenna-mode assignment under sensing, power, and antenna mode constraints. We develop an alternating-optimization-based solution framework mainly with the aid of weighted minimum mean square error, continuous relaxation-based penalty, and successive convex approximation. Numerical results show that the proposed non-uniform array achieves higher sum-rates than the uniform-array baselines, with particularly large gains when the number of activated antennas is small. Moreover, the proposed non-uniform array can achieve, and in some cases exceed, the performance of uniform array baselines with substantially fewer activated antennas, highlighting geometry-aware non-uniform array design as a compelling alternative to brute-force antenna scaling-based array design.

翻译：本文研究面向单基地集成感知与通信（ISAC）系统的柔性非均匀阵列设计。考虑基站处设置天线池，每根候选天线可动态分配为发射、接收或休眠模式，从而与ISAC预编码设计联合构建非均匀有效阵列。我们通过联合优化ISAC波束赋形方案与天线模式分配，在感知约束、功率约束及天线模式约束下建立总和通信速率最大化问题。提出基于交替优化的求解框架，主要借助加权最小均方误差、连续松弛惩罚及逐次凸逼近技术。数值结果表明：所提非均匀阵列相比均匀阵列基准可实现更高总和速率，尤其在激活天线数较少时增益显著。此外，所提非均匀阵列能以大幅减少的激活天线数量达成甚至超越均匀阵列基准的性能，突显几何感知驱动的非均匀阵列设计可作为暴力天线扩展式阵列设计的极具竞争力的替代方案。